$AEE
AMEREN CORP Stock $aee

$aee Overview Financials Valuation SEC Filings Company Website

2015 Q4 Form 10-K Financial Statement

#000100291016000205 Filed on February 26, 2016

Income Statement

Concept	2015 Q4	2014 Q4	2014 Q3
Revenue	$1.308B	$1.370B	$1.670B
YoY Change	-4.53%	3.63%	1.95%
Cost Of Revenue	$216.0M	$302.0M	$161.0M
YoY Change	-28.48%	6.34%	-5.29%
Gross Profit	$1.092B	$1.068B	$1.509B
YoY Change	2.25%	2.89%	2.79%
Gross Profit Margin	83.49%	77.96%	90.36%
Selling, General & Admin
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$195.0M	$184.0M	$177.0M
YoY Change	5.98%	10.84%	6.63%
% of Gross Profit	17.86%	17.23%	11.73%
Operating Expenses	$952.0M	$943.0M	$1.109B
YoY Change	0.95%	8.77%	3.55%
Operating Profit	$140.0M	$125.0M	$561.0M
YoY Change	12.0%	-26.9%	-1.06%
Interest Expense	-$82.00M	-$75.00M	$85.00M
YoY Change	9.33%	-27.18%	-3.41%
% of Operating Profit	-58.57%	-60.0%	15.15%
Other Income/Expense, Net	$3.000M	$17.00M	$14.00M
YoY Change	-82.35%	325.0%	-6.67%
Pretax Income	$61.00M	$67.00M	$490.0M
YoY Change	-8.96%	-6.94%	-0.81%
Income Tax	$30.00M	$20.00M	$194.0M
% Of Pretax Income	49.18%	29.85%	39.59%
Net Earnings	$29.00M	$48.00M	$293.0M
YoY Change	-39.58%	29.73%	-2.98%
Net Earnings / Revenue	2.22%	3.5%	17.54%
Basic Earnings Per Share	$0.12	$0.20	$1.21
Diluted Earnings Per Share	$0.12	$0.20	$1.20
COMMON SHARES
Basic Shares Outstanding	242.6M shares		242.6M shares
Diluted Shares Outstanding			244.3M shares

Balance Sheet

Concept	2015 Q4	2014 Q4	2014 Q3
SHORT-TERM ASSETS
Cash & Short-Term Investments	$292.0M	$5.000M	$13.00M
YoY Change	5740.0%	-83.33%	-92.31%
Cash & Equivalents	$292.0M	$5.000M	$13.00M
Short-Term Investments
Other Short-Term Assets	$88.00M	$86.00M	$66.00M
YoY Change	2.33%	1.18%	-38.89%
Inventory	$538.0M	$524.0M	$561.0M
Prepaid Expenses
Receivables	$388.0M	$423.0M	$467.0M
Other Receivables	$98.00M	$81.00M	$117.0M
Total Short-Term Assets	$1.917B	$1.694B	$1.942B
YoY Change	13.16%	-14.1%	-40.67%
LONG-TERM ASSETS
Property, Plant & Equipment	$18.80B	$17.42B	$16.99B
YoY Change	7.89%	7.52%	7.31%
Goodwill	$411.0M	$411.0M	$411.0M
YoY Change	0.0%	0.0%	0.0%
Intangibles			$20.00M
YoY Change			5.26%
Long-Term Investments	$556.0M	$549.0M	$529.0M
YoY Change	1.28%	11.13%	15.25%
Other Assets	$575.0M	$629.0M	$724.0M
YoY Change	-8.59%	-12.64%	9.7%
Total Long-Term Assets	$21.72B	$20.60B	$19.93B
YoY Change	5.48%	8.0%	4.3%
TOTAL ASSETS
Total Short-Term Assets	$1.917B	$1.694B	$1.942B
Total Long-Term Assets	$21.72B	$20.60B	$19.93B
Total Assets	$23.64B	$22.29B	$21.88B
YoY Change	6.06%	5.93%	-2.27%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$777.0M	$711.0M	$466.0M
YoY Change	9.28%	-11.79%	12.56%
Accrued Expenses	$89.00M	$85.00M	$105.0M
YoY Change	4.71%	-1.16%	-12.5%
Deferred Revenue
YoY Change
Short-Term Debt	$301.0M	$714.0M	$753.0M
YoY Change	-57.84%	94.02%
Long-Term Debt Due	$395.0M	$120.0M	$119.0M
YoY Change	229.17%	-77.53%	-86.54%
Total Short-Term Liabilities	$2.093B	$2.249B	$2.119B
YoY Change	-6.94%	-8.61%	-34.36%
LONG-TERM LIABILITIES
Long-Term Debt	$6.880B	$6.085B	$5.825B
YoY Change	13.06%	10.56%	10.45%
Other Long-Term Liabilities	$531.0M	$514.0M	$522.0M
YoY Change	3.31%	-4.46%	-2.25%
Total Long-Term Liabilities	$7.411B	$6.599B	$6.347B
YoY Change	12.3%	9.22%	9.28%
TOTAL LIABILITIES
Total Short-Term Liabilities	$2.093B	$2.249B	$2.119B
Total Long-Term Liabilities	$7.411B	$6.599B	$6.347B
Total Liabilities	$9.504B	$8.848B	$8.466B
YoY Change	7.41%	4.06%	-6.31%
SHAREHOLDERS EQUITY
Retained Earnings	$1.331B	$1.103B	$1.154B
YoY Change	20.67%	21.61%	19.34%
Common Stock	$2.000M	$2.000M	$2.000M
YoY Change	0.0%	0.0%	0.0%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$6.946B	$6.713B	$6.774B
YoY Change
Total Liabilities & Shareholders Equity	$23.64B	$22.29B	$21.88B
YoY Change	6.06%	5.93%	-2.27%

Cashflow Statement

Concept	2015 Q4	2014 Q4	2014 Q3
OPERATING ACTIVITIES
Net Income	$29.00M	$48.00M	$293.0M
YoY Change	-39.58%	29.73%	-2.98%
Depreciation, Depletion And Amortization	$195.0M	$184.0M	$177.0M
YoY Change	5.98%	10.84%	6.63%
Cash From Operating Activities	$489.0M	$348.0M	$549.0M
YoY Change	40.52%	-8.18%	0.55%
INVESTING ACTIVITIES
Capital Expenditures	-$607.0M	-$521.0M	-$429.0M
YoY Change	16.51%	16.55%	13.79%
Acquisitions
YoY Change
Other Investing Activities	-$7.000M	$16.00M	-$13.00M
YoY Change	-143.75%	-106.58%	-31.58%
Cash From Investing Activities	-$614.0M	-$505.0M	-$442.0M
YoY Change	21.58%	-26.81%	11.62%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	345.0M	149.0M	-140.0M
YoY Change	131.54%	1.36%	6.87%
NET CHANGE
Cash From Operating Activities	489.0M	348.0M	549.0M
Cash From Investing Activities	-614.0M	-505.0M	-442.0M
Cash From Financing Activities	345.0M	149.0M	-140.0M
Net Change In Cash	220.0M	-8.000M	-33.00M
YoY Change	-2850.0%	-95.12%	-273.68%
FREE CASH FLOW
Cash From Operating Activities	$489.0M	$348.0M	$549.0M
Capital Expenditures	-$607.0M	-$521.0M	-$429.0M
Free Cash Flow	$1.096B	$869.0M	$978.0M
YoY Change	26.12%	5.21%	5.96%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2014Q4	aee	Accumulated Depreciation Capital Lease AccumulatedDepreciationCapitalLease	66000000	USD
CY2015Q4	aee	Accumulated Depreciation Capital Lease AccumulatedDepreciationCapitalLease	72000000	USD
CY2015	aee	Aggregate Maximum Assessment Per Incident Under Price Andersen Liability Provisions Of Atomic Energy Act AggregateMaximumAssessmentPerIncidentUnderPriceAndersenLiabilityProvisionsOfAtomicEnergyAct	127000000	USD
CY2015	aee	Aggregate Nuclear Power Industry Insurance Policy Limit For Losses From Terrorist Attacks Within Twelve Month Period AggregateNuclearPowerIndustryInsurancePolicyLimitForLossesFromTerroristAttacksWithinTwelveMonthPeriod	3240000000	USD
CY2015	aee	Amount Of Additional Weekly Indemnity Coverage Commencing After Initial Indemnity Coverage AmountOfAdditionalWeeklyIndemnityCoverageCommencingAfterInitialIndemnityCoverage	3600000	USD
CY2015	aee	Amount Of Coverage In Excess Of Primary Property Liability Coverage AmountOfCoverageInExcessOfPrimaryPropertyLiabilityCoverage	2250000000.00	USD
CY2015	aee	Amount Of Weekly Indemnity Coverage Commencing Eight Weeks After Power Outage AmountOfWeeklyIndemnityCoverageCommencingEightWeeksAfterPowerOutage	4500000	USD
CY2015	aee	Amount Of Weekly Indemnity Coverage Thereafter Not Exceeding Policy Limit AmountOfWeeklyIndemnityCoverageThereafterNotExceedingPolicyLimit	490000000	USD
CY2015Q4	aee	Annual Obligation For Real Estate Leases And Railroad Licenses AnnualObligationForRealEstateLeasesAndRailroadLicenses	3000000	USD
CY2015Q4	aee	Capital And Operating Lease Obligations Due CapitalAndOperatingLeaseObligationsDue	380000000	USD
CY2015Q4	aee	Capital And Operating Lease Obligations Due Current CapitalAndOperatingLeaseObligationsDueCurrent	20000000	USD
CY2015Q4	aee	Capital And Operating Lease Obligations Due In Year Four CapitalAndOperatingLeaseObligationsDueInYearFour	18000000	USD
CY2015Q4	aee	Capital And Operating Lease Obligations Due In Year One CapitalAndOperatingLeaseObligationsDueInYearOne	19000000	USD
CY2015Q4	aee	Capital And Operating Lease Obligations Due In Year Three CapitalAndOperatingLeaseObligationsDueInYearThree	19000000	USD
CY2015Q4	aee	Capital And Operating Lease Obligations Due In Year Two CapitalAndOperatingLeaseObligationsDueInYearTwo	18000000	USD
CY2015Q4	aee	Capital And Operating Lease Obligations Due Thereafter CapitalAndOperatingLeaseObligationsDueThereafter	286000000	USD
CY2015Q4	aee	Capital Leases Future Minimum Payments Interest Included In Payments Current CapitalLeasesFutureMinimumPaymentsInterestIncludedInPaymentsCurrent	27000000	USD
CY2015Q4	aee	Capital Leases Future Minimum Payments Interest Included In Payments Due In Five Years CapitalLeasesFutureMinimumPaymentsInterestIncludedInPaymentsDueInFiveYears	25000000	USD
CY2015Q4	aee	Capital Leases Future Minimum Payments Interest Included In Payments Due In Four Years CapitalLeasesFutureMinimumPaymentsInterestIncludedInPaymentsDueInFourYears	25000000	USD
CY2015Q4	aee	Capital Leases Future Minimum Payments Interest Included In Payments Due In Three Years CapitalLeasesFutureMinimumPaymentsInterestIncludedInPaymentsDueInThreeYears	26000000	USD
CY2015Q4	aee	Capital Leases Future Minimum Payments Interest Included In Payments Due In Two Years CapitalLeasesFutureMinimumPaymentsInterestIncludedInPaymentsDueInTwoYears	27000000	USD
CY2015Q4	aee	Capital Leases Future Minimum Payments Interest Included In Payments Thereafter CapitalLeasesFutureMinimumPaymentsInterestIncludedInPaymentsThereafter	73000000	USD
CY2015Q4	aee	Capital Leases Future Minimum Payments Present Value Of Net Minimum Payments Current CapitalLeasesFutureMinimumPaymentsPresentValueOfNetMinimumPaymentsCurrent	6000000	USD
CY2015Q4	aee	Capital Leases Future Minimum Payments Present Value Of Net Minimum Payments Due In Five Years CapitalLeasesFutureMinimumPaymentsPresentValueOfNetMinimumPaymentsDueInFiveYears	7000000	USD
CY2015Q4	aee	Capital Leases Future Minimum Payments Present Value Of Net Minimum Payments Due In Four Years CapitalLeasesFutureMinimumPaymentsPresentValueOfNetMinimumPaymentsDueInFourYears	7000000	USD
CY2015Q4	aee	Capital Leases Future Minimum Payments Present Value Of Net Minimum Payments Due In Three Years CapitalLeasesFutureMinimumPaymentsPresentValueOfNetMinimumPaymentsDueInThreeYears	6000000	USD
CY2015Q4	aee	Capital Leases Future Minimum Payments Present Value Of Net Minimum Payments Due In Two Years CapitalLeasesFutureMinimumPaymentsPresentValueOfNetMinimumPaymentsDueInTwoYears	6000000	USD
CY2015Q4	aee	Capital Leases Future Minimum Payments Present Value Of Net Minimum Payments Thereafter CapitalLeasesFutureMinimumPaymentsPresentValueOfNetMinimumPaymentsThereafter	256000000	USD
CY2013	aee	Comprehensive Income Loss From Continuing Operations Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeLossFromContinuingOperationsNetOfTaxAttributableToNoncontrollingInterest	6000000	USD
CY2014	aee	Comprehensive Income Loss From Continuing Operations Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeLossFromContinuingOperationsNetOfTaxAttributableToNoncontrollingInterest	6000000	USD
CY2015	aee	Comprehensive Income Loss From Continuing Operations Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeLossFromContinuingOperationsNetOfTaxAttributableToNoncontrollingInterest	6000000	USD
CY2013	aee	Comprehensive Income Loss From Continuing Operations Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeLossFromContinuingOperationsNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	548000000	USD
CY2014	aee	Comprehensive Income Loss From Continuing Operations Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeLossFromContinuingOperationsNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	581000000	USD
CY2015	aee	Comprehensive Income Loss From Continuing Operations Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeLossFromContinuingOperationsNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	591000000	USD
CY2013	aee	Comprehensive Income Loss From Continuing Operations Net Of Tax Portion Attributable To Parent ComprehensiveIncomeLossFromContinuingOperationsNetOfTaxPortionAttributableToParent	542000000	USD
CY2014	aee	Comprehensive Income Loss From Continuing Operations Net Of Tax Portion Attributable To Parent ComprehensiveIncomeLossFromContinuingOperationsNetOfTaxPortionAttributableToParent	575000000	USD
CY2015	aee	Comprehensive Income Loss From Continuing Operations Net Of Tax Portion Attributable To Parent ComprehensiveIncomeLossFromContinuingOperationsNetOfTaxPortionAttributableToParent	585000000	USD
CY2013	aee	Comprehensive Income Loss From Discontinued Operations Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest	1000000	USD
CY2014	aee	Comprehensive Income Loss From Discontinued Operations Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest	0	USD
CY2013	aee	Comprehensive Income Loss From Discontinued Operations Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeLossFromDiscontinuedOperationsNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-241000000	USD
CY2014	aee	Comprehensive Income Loss From Discontinued Operations Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeLossFromDiscontinuedOperationsNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-1000000	USD
CY2015	aee	Comprehensive Income Loss From Discontinued Operations Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeLossFromDiscontinuedOperationsNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	51000000	USD
CY2013	aee	Comprehensive Income Loss From Discontinued Operations Net Of Tax Portion Attributable To Parent ComprehensiveIncomeLossFromDiscontinuedOperationsNetOfTaxPortionAttributableToParent	-242000000	USD
CY2014	aee	Comprehensive Income Loss From Discontinued Operations Net Of Tax Portion Attributable To Parent ComprehensiveIncomeLossFromDiscontinuedOperationsNetOfTaxPortionAttributableToParent	-1000000	USD
CY2015	aee	Comprehensive Income Loss From Discontinued Operations Net Of Tax Portion Attributable To Parent ComprehensiveIncomeLossFromDiscontinuedOperationsNetOfTaxPortionAttributableToParent	51000000	USD
CY2013	aee	Contributionsto Note Receivable ContributionstoNoteReceivable	5000000	USD
CY2014	aee	Contributionsto Note Receivable ContributionstoNoteReceivable	89000000	USD
CY2015	aee	Contributionsto Note Receivable ContributionstoNoteReceivable	8000000	USD
CY2015	aee	Debt Default Provision Excess DebtDefaultProvisionExcess	25000000	USD
CY2014Q4	aee	Deferred Tax Liabilities Revenue Requirement Reconciliation Adjustment DeferredTaxLiabilitiesRevenueRequirementReconciliationAdjustment	69000000	USD
CY2015Q4	aee	Deferred Tax Liabilities Revenue Requirement Reconciliation Adjustment DeferredTaxLiabilitiesRevenueRequirementReconciliationAdjustment	66000000	USD
CY2015Q4	aee	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Changein Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationChangeinDiscountRate	0.0050
CY2015Q4	aee	Defined Benefit Plan Estimated Future Employer Contributions Over Next Five Years DefinedBenefitPlanEstimatedFutureEmployerContributionsOverNextFiveYears	280000000	USD
CY2015	aee	Defined Benefit Plan Future Amortization Of Prior Service Cost Credit Period DefinedBenefitPlanFutureAmortizationOfPriorServiceCostCreditPeriod	P10Y
CY2015	aee	Defined Benefit Plan Number Of High Quality Bonds Used To Determine Yield Curve DefinedBenefitPlanNumberOfHighQualityBondsUsedToDetermineYieldCurve	700	bond
CY2014Q4	aee	Disposal Group Including Discontinued Operation Asset Retirement Obligations Current DisposalGroupIncludingDiscontinuedOperationAssetRetirementObligationsCurrent	32000000	USD
CY2015Q4	aee	Disposal Group Including Discontinued Operation Asset Retirement Obligations Current DisposalGroupIncludingDiscontinuedOperationAssetRetirementObligationsCurrent	28000000	USD
CY2013	aee	Disposal Group Including Discontinued Operation Other Income Loss DisposalGroupIncludingDiscontinuedOperationOtherIncomeLoss	-1000000	USD
CY2014	aee	Disposal Group Including Discontinued Operation Other Income Loss DisposalGroupIncludingDiscontinuedOperationOtherIncomeLoss	0	USD
CY2015	aee	Disposal Group Including Discontinued Operation Other Income Loss DisposalGroupIncludingDiscontinuedOperationOtherIncomeLoss	0	USD
CY2013	aee	Donations Donations	12000000	USD
CY2014	aee	Donations Donations	10000000	USD
CY2015	aee	Donations Donations	15000000	USD
CY2015Q4	aee	Insurance Aggregate Maximum Coverage InsuranceAggregateMaximumCoverage	13489000000	USD
CY2015	aee	Maximum Annual Payment In Calendar Year Per Reactor Incident Under Price Andersen Liability Provisions Of Atomic Energy Act MaximumAnnualPaymentInCalendarYearPerReactorIncidentUnderPriceAndersenLiabilityProvisionsOfAtomicEnergyAct	19000000	USD
CY2015	aee	Maximum Annual Payment Per Incident At Licensed Commercia Lnuclear Reactor MaximumAnnualPaymentPerIncidentAtLicensedCommerciaLnuclearReactor	19000000	USD
CY2015	aee	Number Of Additional Weeks After Initial Indemnity Coverage For Power Outage NumberOfAdditionalWeeksAfterInitialIndemnityCoverageForPowerOutage	P1Y4M10D
CY2015Q4	aee	Number Of Combustion Turbine Electric Generation Equipment Under Capital Lease Agreements NumberOfCombustionTurbineElectricGenerationEquipmentUnderCapitalLeaseAgreements	2	equipment
CY2015	aee	Numberofweeksofcoverageafterthefirsteightweeksofanoutage Numberofweeksofcoverageafterthefirsteightweeksofanoutage	P1Y
CY2015	aee	Nwf Fee Number Of Mills NwfFeeNumberOfMills	1	mill
CY2013	aee	Other Comprehensive Income Loss Discontinued Operations Tax OtherComprehensiveIncomeLossDiscontinuedOperationsTax	-10000000	USD
CY2015Q4	aee	Insurance Maximum Coverage Per Incident InsuranceMaximumCoveragePerIncident	127000000	USD
CY2014	aee	Other Comprehensive Income Loss Discontinued Operations Tax OtherComprehensiveIncomeLossDiscontinuedOperationsTax	0	USD
CY2015	aee	Other Comprehensive Income Loss Discontinued Operations Tax OtherComprehensiveIncomeLossDiscontinuedOperationsTax	0	USD
CY2013	aee	Other Comprehensive Income Loss From Discontinued Operations Net Of Tax Including Portion Attributable To Noncontrolling Interest OtherComprehensiveIncomeLossFromDiscontinuedOperationsNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-18000000	USD
CY2014	aee	Other Comprehensive Income Loss From Discontinued Operations Net Of Tax Including Portion Attributable To Noncontrolling Interest OtherComprehensiveIncomeLossFromDiscontinuedOperationsNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	0	USD
CY2014Q4	aee	Property Plant And Equipment Net Before Construction Work In Progress PropertyPlantAndEquipmentNetBeforeConstructionWorkInProgress	16439000000	USD
CY2015Q4	aee	Property Plant And Equipment Net Before Construction Work In Progress PropertyPlantAndEquipmentNetBeforeConstructionWorkInProgress	17256000000	USD
CY2015Q4	aee	Property Plant And Equipment Number Of Capital Lease Agreements PropertyPlantAndEquipmentNumberOfCapitalLeaseAgreements	2	equipment
CY2014Q4	aee	Receivables Payables And Accrued Income Net ReceivablesPayablesAndAccruedIncomeNet	2000000	USD
CY2015Q4	aee	Receivables Payables And Accrued Income Net ReceivablesPayablesAndAccruedIncomeNet	-1000000	USD
CY2015	dei	Amendment Flag AmendmentFlag	false
CY2015	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2015	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2015	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2015
CY2015	dei	Document Period End Date DocumentPeriodEndDate	2015-12-31
CY2015	dei	Document Type DocumentType	10-K
CY2015	dei	Entity Central Index Key EntityCentralIndexKey	0001002910
CY2016Q1	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	242634798	shares
CY2015	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2015	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2015Q2	dei	Entity Public Float EntityPublicFloat	9142479189	USD
CY2015	dei	Entity Registrant Name EntityRegistrantName	AMEREN CORP
CY2015	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2015	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes
CY2015	dei	Trading Symbol TradingSymbol	AEE
CY2014Q4	us-gaap	Accounts Payable And Accrued Liabilities Current AccountsPayableAndAccruedLiabilitiesCurrent	711000000	USD
CY2015Q4	us-gaap	Accounts Payable And Accrued Liabilities Current AccountsPayableAndAccruedLiabilitiesCurrent	777000000	USD
CY2014Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	423000000	USD
CY2015Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	388000000	USD
CY2014Q4	us-gaap	Accumulated Deferred Investment Tax Credit AccumulatedDeferredInvestmentTaxCredit	64000000	USD
CY2015Q4	us-gaap	Accumulated Deferred Investment Tax Credit AccumulatedDeferredInvestmentTaxCredit	60000000	USD
CY2014Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	9759000000	USD
CY2015Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	10347000000	USD
CY2014Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-9000000	USD
CY2015Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-3000000	USD
CY2015Q4	us-gaap	Additional Collateral Aggregate Fair Value AdditionalCollateralAggregateFairValue	143000000	USD
CY2014Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	5617000000	USD
CY2015Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	5616000000	USD
CY2013	us-gaap	Adjustment For Amortization AdjustmentForAmortization	71000000	USD
CY2015Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	6000000	USD
CY2014	us-gaap	Adjustment For Amortization AdjustmentForAmortization	81000000	USD
CY2015	us-gaap	Adjustment For Amortization AdjustmentForAmortization	97000000	USD
CY2013	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	20000000	USD
CY2014	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	19000000	USD
CY2015	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	19000000	USD
CY2014Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	21000000	USD
CY2015Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	19000000	USD
CY2013	us-gaap	Amortization Of Financing Costs And Discounts AmortizationOfFinancingCostsAndDiscounts	24000000	USD
CY2014	us-gaap	Amortization Of Financing Costs And Discounts AmortizationOfFinancingCostsAndDiscounts	22000000	USD
CY2015	us-gaap	Amortization Of Financing Costs And Discounts AmortizationOfFinancingCostsAndDiscounts	22000000	USD
CY2013	us-gaap	Asset Impairment Charges AssetImpairmentCharges	0	USD
CY2015	us-gaap	Asset Impairment Charges AssetImpairmentCharges	69000000	USD
CY2013Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	369000000	USD
CY2014Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	396000000	USD
CY2015Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	623000000	USD
CY2014	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	21000000	USD
CY2015	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	23000000	USD
CY2014	us-gaap	Asset Retirement Obligation Liabilities Incurred AssetRetirementObligationLiabilitiesIncurred	2000000	USD
CY2015	us-gaap	Asset Retirement Obligation Liabilities Incurred AssetRetirementObligationLiabilitiesIncurred	3000000	USD
CY2014	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled	2000000	USD
CY2015	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled	2000000	USD
CY2014	us-gaap	Asset Retirement Obligation Revision Of Estimate AssetRetirementObligationRevisionOfEstimate	6000000	USD
CY2015	us-gaap	Asset Retirement Obligation Revision Of Estimate AssetRetirementObligationRevisionOfEstimate	203000000	USD
CY2014Q4	us-gaap	Asset Retirement Obligations Noncurrent AssetRetirementObligationsNoncurrent	396000000	USD
CY2015Q4	us-gaap	Asset Retirement Obligations Noncurrent AssetRetirementObligationsNoncurrent	618000000	USD
CY2014Q4	us-gaap	Assets Assets	22289000000	USD
CY2015Q4	us-gaap	Assets Assets	23640000000	USD
CY2014Q4	us-gaap	Assets Current AssetsCurrent	1694000000	USD
CY2015Q4	us-gaap	Assets Current AssetsCurrent	1917000000	USD
CY2014Q4	us-gaap	Assets Fair Value Disclosure AssetsFairValueDisclosure	566000000	USD
CY2015Q4	us-gaap	Assets Fair Value Disclosure AssetsFairValueDisclosure	575000000	USD
CY2013Q4	us-gaap	Assets Of Disposal Group Including Discontinued Operation Current AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent	165000000	USD
CY2014Q4	us-gaap	Assets Of Disposal Group Including Discontinued Operation Current AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent	15000000	USD
CY2015Q4	us-gaap	Assets Of Disposal Group Including Discontinued Operation Current AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent	14000000	USD
CY2014Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	237000000	USD
CY2015Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	226000000	USD
CY2015Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	191000000	USD
CY2014Q4	us-gaap	Available For Sale Securities AvailableForSaleSecurities	316000000	USD
CY2015Q4	us-gaap	Available For Sale Securities AvailableForSaleSecurities	341000000	USD
CY2014Q4	us-gaap	Available For Sale Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	4000000	USD
CY2015Q4	us-gaap	Available For Sale Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	11000000	USD
CY2015Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	5000000	USD
CY2015Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	11000000	USD
CY2015Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue	160000000	USD
CY2015Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	152000000	USD
CY2015Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	8000000	USD
CY2015Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	42000000	USD
CY2015Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	41000000	USD
CY2015Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost	106000000	USD
CY2015Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	105000000	USD
CY2015Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	43000000	USD
CY2015Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	43000000	USD
CY2015Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	189000000	USD
CY2013	us-gaap	Available For Sale Securities Gross Realized Gains AvailableForSaleSecuritiesGrossRealizedGains	7000000	USD
CY2014	us-gaap	Available For Sale Securities Gross Realized Gains AvailableForSaleSecuritiesGrossRealizedGains	7000000	USD
CY2015	us-gaap	Available For Sale Securities Gross Realized Gains AvailableForSaleSecuritiesGrossRealizedGains	8000000	USD
CY2013	us-gaap	Available For Sale Securities Gross Realized Losses AvailableForSaleSecuritiesGrossRealizedLosses	5000000	USD
CY2014	us-gaap	Available For Sale Securities Gross Realized Losses AvailableForSaleSecuritiesGrossRealizedLosses	2000000	USD
CY2015	us-gaap	Available For Sale Securities Gross Realized Losses AvailableForSaleSecuritiesGrossRealizedLosses	2000000	USD
CY2013	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	175000000	USD
CY2014	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	181000000	USD
CY2015	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	235000000	USD
CY2015Q4	us-gaap	Capital Leased Assets Gross CapitalLeasedAssetsGross	233000000	USD
CY2015Q4	us-gaap	Capital Leases Future Minimum Payments Due CapitalLeasesFutureMinimumPaymentsDue	491000000	USD
CY2015Q4	us-gaap	Capital Leases Future Minimum Payments Due Current CapitalLeasesFutureMinimumPaymentsDueCurrent	33000000	USD
CY2015Q4	us-gaap	Capital Leases Future Minimum Payments Due In Five Years CapitalLeasesFutureMinimumPaymentsDueInFiveYears	32000000	USD
CY2015Q4	us-gaap	Capital Leases Future Minimum Payments Due In Four Years CapitalLeasesFutureMinimumPaymentsDueInFourYears	32000000	USD
CY2015Q4	us-gaap	Capital Leases Future Minimum Payments Due In Three Years CapitalLeasesFutureMinimumPaymentsDueInThreeYears	32000000	USD
CY2015Q4	us-gaap	Capital Leases Future Minimum Payments Due In Two Years CapitalLeasesFutureMinimumPaymentsDueInTwoYears	33000000	USD
CY2015Q4	us-gaap	Capital Leases Future Minimum Payments Due Thereafter CapitalLeasesFutureMinimumPaymentsDueThereafter	329000000	USD
CY2015Q4	us-gaap	Capital Leases Future Minimum Payments Interest Included In Payments CapitalLeasesFutureMinimumPaymentsInterestIncludedInPayments	203000000	USD
CY2015Q4	us-gaap	Capital Leases Future Minimum Payments Present Value Of Net Minimum Payments CapitalLeasesFutureMinimumPaymentsPresentValueOfNetMinimumPayments	288000000	USD
CY2012Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	209000000	USD
CY2013Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	30000000	USD
CY2014Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	5000000	USD
CY2015Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	292000000	USD
CY2013	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	-179000000	USD
CY2014	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	-25000000	USD
CY2015	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	287000000	USD
CY2013	us-gaap	Cash Provided By Used In Investing Activities Discontinued Operations CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations	-283000000	USD
CY2014	us-gaap	Cash Provided By Used In Investing Activities Discontinued Operations CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations	139000000	USD
CY2015	us-gaap	Cash Provided By Used In Investing Activities Discontinued Operations CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations	-25000000	USD
CY2013	us-gaap	Cash Provided By Used In Operating Activities Discontinued Operations CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations	57000000	USD
CY2014	us-gaap	Cash Provided By Used In Operating Activities Discontinued Operations CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations	-6000000	USD
CY2015	us-gaap	Cash Provided By Used In Operating Activities Discontinued Operations CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations	-4000000	USD
CY2015Q4	us-gaap	Collateral Already Posted Aggregate Fair Value CollateralAlreadyPostedAggregateFairValue	12000000	USD
CY2014Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2015Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2013	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	1.6
CY2014	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	1.61
CY2015	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	1.655
CY2014Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2015Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2014Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	400000000	shares
CY2015Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	400000000	shares
CY2013Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	242600000	shares
CY2014Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	242600000	shares
CY2015Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	242600000	shares
CY2014Q4	us-gaap	Common Stock Value CommonStockValue	2000000	USD
CY2015Q4	us-gaap	Common Stock Value CommonStockValue	2000000	USD
CY2013	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	300000000	USD
CY2014	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	574000000	USD
CY2015	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	636000000	USD
CY2013	us-gaap	Cost Of Goods Sold Depreciation Depletion And Amortization CostOfGoodsSoldDepreciationDepletionAndAmortization	706000000	USD
CY2014	us-gaap	Cost Of Goods Sold Depreciation Depletion And Amortization CostOfGoodsSoldDepreciationDepletionAndAmortization	745000000	USD
CY2015	us-gaap	Cost Of Goods Sold Depreciation Depletion And Amortization CostOfGoodsSoldDepreciationDepletionAndAmortization	796000000	USD
CY2013	us-gaap	Cost Of Natural Gas Purchases CostOfNaturalGasPurchases	526000000	USD
CY2014	us-gaap	Cost Of Natural Gas Purchases CostOfNaturalGasPurchases	615000000	USD
CY2015	us-gaap	Cost Of Natural Gas Purchases CostOfNaturalGasPurchases	415000000	USD
CY2013	us-gaap	Cost Of Purchased Power CostOfPurchasedPower	508000000	USD
CY2014	us-gaap	Cost Of Purchased Power CostOfPurchasedPower	461000000	USD
CY2015	us-gaap	Cost Of Purchased Power CostOfPurchasedPower	514000000	USD
CY2013	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	-118000000	USD
CY2014	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	-37000000	USD
CY2015	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	-2000000	USD
CY2013	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	19000000	USD
CY2014	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	-37000000	USD
CY2015	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	-4000000	USD
CY2014Q4	us-gaap	Decommissioning Fund Investments DecommissioningFundInvestments	549000000	USD
CY2015Q4	us-gaap	Decommissioning Fund Investments DecommissioningFundInvestments	556000000	USD
CY2014Q4	us-gaap	Decommissioning Trust Assets Amount DecommissioningTrustAssetsAmount	547000000	USD
CY2015Q4	us-gaap	Decommissioning Trust Assets Amount DecommissioningTrustAssetsAmount	557000000	USD
CY2013	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	368000000	USD
CY2014	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	369000000	USD
CY2015	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	299000000	USD
CY2014Q4	us-gaap	Deferred Income Taxes And Other Assets Current DeferredIncomeTaxesAndOtherAssetsCurrent	352000000	USD
CY2013	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	410000000	USD
CY2014	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	451000000	USD
CY2015	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	369000000	USD
CY2013	us-gaap	Deferred Other Tax Expense Benefit DeferredOtherTaxExpenseBenefit	-6000000	USD
CY2014	us-gaap	Deferred Other Tax Expense Benefit DeferredOtherTaxExpenseBenefit	-6000000	USD
CY2015	us-gaap	Deferred Other Tax Expense Benefit DeferredOtherTaxExpenseBenefit	-6000000	USD
CY2013	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	48000000	USD
CY2014	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	88000000	USD
CY2015	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	76000000	USD
CY2014Q4	us-gaap	Deferred Tax Assets Charitable Contribution Carryforwards DeferredTaxAssetsCharitableContributionCarryforwards	19000000	USD
CY2015Q4	us-gaap	Deferred Tax Assets Charitable Contribution Carryforwards DeferredTaxAssetsCharitableContributionCarryforwards	10000000	USD
CY2014Q4	us-gaap	Deferred Tax Assets Net Noncurrent DeferredTaxAssetsNetNoncurrent	13000000	USD
CY2015Q4	us-gaap	Deferred Tax Assets Net Noncurrent DeferredTaxAssetsNetNoncurrent	6000000	USD
CY2015Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	6000000	USD
CY2014Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits	220000000	USD
CY2015Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits	207000000	USD
CY2014Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Asset Retirement Obligations DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAssetRetirementObligations	675000000	USD
CY2015Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Asset Retirement Obligations DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAssetRetirementObligations	603000000	USD
CY2014Q4	us-gaap	Deferred Tax Assets Valuation Allowance Noncurrent DeferredTaxAssetsValuationAllowanceNoncurrent	-6000000	USD
CY2015Q4	us-gaap	Deferred Tax Assets Valuation Allowance Noncurrent DeferredTaxAssetsValuationAllowanceNoncurrent	4000000	USD
CY2014Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	3571000000	USD
CY2015Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	3885000000	USD
CY2014Q4	us-gaap	Deferred Tax Liabilities Noncurrent DeferredTaxLiabilitiesNoncurrent	3571000000	USD
CY2015Q4	us-gaap	Deferred Tax Liabilities Noncurrent DeferredTaxLiabilitiesNoncurrent	3885000000	USD
CY2014Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	134000000	USD
CY2014Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	4185000000	USD
CY2015Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	4555000000	USD
CY2014Q4	us-gaap	Deferred Tax Liabilities Regulatory Assets And Liabilities DeferredTaxLiabilitiesRegulatoryAssetsAndLiabilities	78000000	USD
CY2015Q4	us-gaap	Deferred Tax Liabilities Regulatory Assets And Liabilities DeferredTaxLiabilitiesRegulatoryAssetsAndLiabilities	80000000	USD
CY2014Q4	us-gaap	Defined Benefit Plan Funded Status Of Plan DefinedBenefitPlanFundedStatusOfPlan	710000000	USD
CY2015Q4	us-gaap	Defined Benefit Plan Funded Status Of Plan DefinedBenefitPlanFundedStatusOfPlan	567000000	USD
CY2013	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	666000000	USD
CY2014	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	710000000	USD
CY2015	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	777000000	USD
CY2015Q4	us-gaap	Derivative Net Liability Position Aggregate Fair Value DerivativeNetLiabilityPositionAggregateFairValue	165000000	USD
CY2013	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Before Income Tax DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax	-210000000	USD
CY2014	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Before Income Tax DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax	-1000000	USD
CY2015	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Before Income Tax DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax	1000000	USD
CY2013	us-gaap	Discontinued Operation Tax Effect Of Discontinued Operation DiscontinuedOperationTaxEffectOfDiscontinuedOperation	13000000	USD
CY2014	us-gaap	Discontinued Operation Tax Effect Of Discontinued Operation DiscontinuedOperationTaxEffectOfDiscontinuedOperation	0	USD
CY2015	us-gaap	Discontinued Operation Tax Effect Of Discontinued Operation DiscontinuedOperationTaxEffectOfDiscontinuedOperation	-50000000	USD
CY2014Q4	us-gaap	Disposal Group Including Discontinued Operation Accounts Payable DisposalGroupIncludingDiscontinuedOperationAccountsPayable	1000000	USD
CY2015Q4	us-gaap	Disposal Group Including Discontinued Operation Accounts Payable DisposalGroupIncludingDiscontinuedOperationAccountsPayable	1000000	USD
CY2014Q4	us-gaap	Disposal Group Including Discontinued Operation Deferred Tax Assets DisposalGroupIncludingDiscontinuedOperationDeferredTaxAssets	15000000	USD
CY2015Q4	us-gaap	Disposal Group Including Discontinued Operation Deferred Tax Assets DisposalGroupIncludingDiscontinuedOperationDeferredTaxAssets	14000000	USD
CY2013	us-gaap	Disposal Group Including Discontinued Operation Interest Expense DisposalGroupIncludingDiscontinuedOperationInterestExpense	39000000	USD
CY2014	us-gaap	Disposal Group Including Discontinued Operation Interest Expense DisposalGroupIncludingDiscontinuedOperationInterestExpense	0	USD
CY2015	us-gaap	Disposal Group Including Discontinued Operation Interest Expense DisposalGroupIncludingDiscontinuedOperationInterestExpense	0	USD
CY2013	us-gaap	Disposal Group Including Discontinued Operation Operating Expense DisposalGroupIncludingDiscontinuedOperationOperatingExpense	1207000000	USD
CY2014	us-gaap	Disposal Group Including Discontinued Operation Operating Expense DisposalGroupIncludingDiscontinuedOperationOperatingExpense	2000000	USD
CY2015	us-gaap	Disposal Group Including Discontinued Operation Operating Expense DisposalGroupIncludingDiscontinuedOperationOperatingExpense	-1000000	USD
CY2014	us-gaap	Electric Utility Revenue ElectricUtilityRevenue	4913000000	USD
CY2015	us-gaap	Electric Utility Revenue ElectricUtilityRevenue	5180000000	USD
CY2013	us-gaap	Employee Service Share Based Compensation Cash Flow Effect Cash Used To Settle Awards EmployeeServiceShareBasedCompensationCashFlowEffectCashUsedToSettleAwards	11000000	USD
CY2014	us-gaap	Employee Service Share Based Compensation Cash Flow Effect Cash Used To Settle Awards EmployeeServiceShareBasedCompensationCashFlowEffectCashUsedToSettleAwards	33000000	USD
CY2015	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1	P23M
CY2013	us-gaap	Disposal Group Including Discontinued Operation Operating Income Loss DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss	-170000000	USD
CY2014	us-gaap	Disposal Group Including Discontinued Operation Operating Income Loss DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss	-1000000	USD
CY2015	us-gaap	Disposal Group Including Discontinued Operation Operating Income Loss DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss	1000000	USD
CY2013	us-gaap	Disposal Group Including Discontinued Operation Revenue DisposalGroupIncludingDiscontinuedOperationRevenue	1037000000	USD
CY2014	us-gaap	Disposal Group Including Discontinued Operation Revenue DisposalGroupIncludingDiscontinuedOperationRevenue	1000000	USD
CY2015	us-gaap	Disposal Group Including Discontinued Operation Revenue DisposalGroupIncludingDiscontinuedOperationRevenue	0	USD
CY2013	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.19
CY2014Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.40
CY2014Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.61
CY2014Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.21
CY2014Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.20
CY2014	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.42
CY2015Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.45
CY2015Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.61
CY2015Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.42
CY2015Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.12
CY2015	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.60
CY2013	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.18
CY2014Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.40
CY2014Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.61
CY2014Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.20
CY2014Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.20
CY2014	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.40
CY2015Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.45
CY2015Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.61
CY2015Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.41
CY2015Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.12
CY2015	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.59
CY2013	us-gaap	Earnings Per Share Potentially Dilutive Securities EarningsPerSharePotentiallyDilutiveSecurities	0
CY2014	us-gaap	Earnings Per Share Potentially Dilutive Securities EarningsPerSharePotentiallyDilutiveSecurities	0
CY2015	us-gaap	Earnings Per Share Potentially Dilutive Securities EarningsPerSharePotentiallyDilutiveSecurities	0
CY2013	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.38
CY2014	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.39
CY2015	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.38
CY2013	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.35
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CY2015	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.35
CY2013	us-gaap	Effective Income Tax Rate Reconciliation Deductions EffectiveIncomeTaxRateReconciliationDeductions	0.00
CY2014	us-gaap	Effective Income Tax Rate Reconciliation Deductions EffectiveIncomeTaxRateReconciliationDeductions	0.01
CY2015	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Depreciation EffectiveIncomeTaxRateReconciliationNondeductibleExpenseDepreciation	-0.01
CY2013	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.04
CY2014	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.04
CY2015	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.05
CY2013	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Investment EffectiveIncomeTaxRateReconciliationTaxCreditsInvestment	-0.01
CY2014	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Investment EffectiveIncomeTaxRateReconciliationTaxCreditsInvestment	-0.01
CY2015	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Investment EffectiveIncomeTaxRateReconciliationTaxCreditsInvestment	-0.01
CY2013	us-gaap	Electric Utility Revenue ElectricUtilityRevenue	4832000000	USD
CY2015	us-gaap	Employee Service Share Based Compensation Cash Flow Effect Cash Used To Settle Awards EmployeeServiceShareBasedCompensationCashFlowEffectCashUsedToSettleAwards	27000000	USD
CY2015Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized	21000000	USD
CY2013	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	8000000	USD
CY2014	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	7000000	USD
CY2015	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	7000000	USD
CY2014Q4	us-gaap	Energy Related Inventory Coal EnergyRelatedInventoryCoal	134000000	USD
CY2015Q4	us-gaap	Energy Related Inventory Coal EnergyRelatedInventoryCoal	173000000	USD
CY2014Q4	us-gaap	Energy Related Inventory Gas Stored Underground EnergyRelatedInventoryGasStoredUnderground	127000000	USD
CY2015Q4	us-gaap	Energy Related Inventory Gas Stored Underground EnergyRelatedInventoryGasStoredUnderground	97000000	USD
CY2013	us-gaap	Excise And Sales Taxes ExciseAndSalesTaxes	213000000	USD
CY2014	us-gaap	Excise And Sales Taxes ExciseAndSalesTaxes	215000000	USD
CY2015	us-gaap	Excise And Sales Taxes ExciseAndSalesTaxes	213000000	USD
CY2013	us-gaap	Fuel Costs FuelCosts	845000000	USD
CY2014	us-gaap	Fuel Costs FuelCosts	826000000	USD
CY2015	us-gaap	Fuel Costs FuelCosts	878000000	USD
CY2013	us-gaap	Gas Domestic Regulated Revenue GasDomesticRegulatedRevenue	1006000000	USD
CY2014	us-gaap	Gas Domestic Regulated Revenue GasDomesticRegulatedRevenue	1140000000	USD
CY2015	us-gaap	Gas Domestic Regulated Revenue GasDomesticRegulatedRevenue	918000000	USD
CY2014Q4	us-gaap	Goodwill Goodwill	411000000	USD
CY2015Q4	us-gaap	Goodwill Goodwill	411000000	USD
CY2014Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	294000000	USD
CY2015Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	288000000	USD
CY2013	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	512000000	USD
CY2014Q1	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	97000000	USD
CY2014Q2	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	150000000	USD
CY2014Q3	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	294000000	USD
CY2014Q4	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	46000000	USD
CY2014	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	587000000	USD
CY2015Q1	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	108000000	USD
CY2015Q2	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	98000000	USD
CY2015Q3	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	343000000	USD
CY2015Q4	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	30000000	USD
CY2015	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	579000000	USD
CY2013	us-gaap	Income Loss From Continuing Operations Attributable To Noncontrolling Entity IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity	6000000	USD
CY2014	us-gaap	Income Loss From Continuing Operations Attributable To Noncontrolling Entity IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity	6000000	USD
CY2015	us-gaap	Income Loss From Continuing Operations Attributable To Noncontrolling Entity IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity	6000000	USD
CY2013	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	829000000	USD
CY2014	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	970000000	USD
CY2015	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	948000000	USD
CY2013	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	518000000	USD
CY2014	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	593000000	USD
CY2015	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	585000000	USD
CY2013	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	2.11
CY2014Q1	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.40
CY2014Q2	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.62
CY2014Q3	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.21
CY2014Q4	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.19
CY2014	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	2.42
CY2015Q1	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.45
CY2015Q2	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.40
CY2015Q3	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.42
CY2015Q4	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.12
CY2015	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	2.39
CY2013	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	2.10
CY2014Q1	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.40
CY2014Q2	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.62
CY2014Q3	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.20
CY2014Q4	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.19
CY2014	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	2.40
CY2015Q1	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.45
CY2015Q2	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.40
CY2015Q3	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.41
CY2015Q4	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.12
CY2015	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	2.38
CY2013	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	-223000000	USD
CY2014	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	-1000000	USD
CY2015	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	51000000	USD
CY2013	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-223000000	USD
CY2014Q1	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-1000000	USD
CY2014Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-1000000	USD
CY2014Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-1000000	USD
CY2014Q4	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	2000000	USD
CY2014	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-1000000	USD
CY2015Q1	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	0	USD
CY2015Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	52000000	USD
CY2015Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	0	USD
CY2015Q4	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-1000000	USD
CY2015	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	51000000	USD
CY2013	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	-0.92
CY2014Q1	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	0.00
CY2014Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	-0.01
CY2014Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	0.00
CY2014Q4	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	0.01
CY2014	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	0.00
CY2015Q1	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	0.00
CY2015Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	0.21
CY2015Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	0.00
CY2015Q4	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	0.00
CY2015	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	0.21
CY2013	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	-0.92
CY2014Q1	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	0.00
CY2014Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	-0.01
CY2014Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	0.00
CY2014Q4	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	0.01
CY2014	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	0.00
CY2015Q1	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	0.00
CY2015Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	0.21
CY2015Q3	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	0.00
CY2015Q4	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	0.00
CY2015	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	0.21
CY2013	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	311000000	USD
CY2014	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	377000000	USD
CY2015	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	363000000	USD
CY2013	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	8000000	USD
CY2014	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	-27000000	USD
CY2015	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	-15000000	USD
CY2013	us-gaap	Increase Decrease In Accounts Payable And Accrued Liabilities IncreaseDecreaseInAccountsPayableAndAccruedLiabilities	81000000	USD
CY2014	us-gaap	Increase Decrease In Accounts Payable And Accrued Liabilities IncreaseDecreaseInAccountsPayableAndAccruedLiabilities	10000000	USD
CY2015	us-gaap	Increase Decrease In Accounts Payable And Accrued Liabilities IncreaseDecreaseInAccountsPayableAndAccruedLiabilities	-2000000	USD
CY2013	us-gaap	Increase Decrease In Accrued Taxes Payable IncreaseDecreaseInAccruedTaxesPayable	-195000000	USD
CY2014	us-gaap	Increase Decrease In Accrued Taxes Payable IncreaseDecreaseInAccruedTaxesPayable	-44000000	USD
CY2015	us-gaap	Increase Decrease In Accrued Taxes Payable IncreaseDecreaseInAccruedTaxesPayable	-24000000	USD
CY2013	us-gaap	Increase Decrease In Deposit Other Assets IncreaseDecreaseInDepositOtherAssets	-41000000	USD
CY2014	us-gaap	Increase Decrease In Deposit Other Assets IncreaseDecreaseInDepositOtherAssets	-22000000	USD
CY2015	us-gaap	Increase Decrease In Deposit Other Assets IncreaseDecreaseInDepositOtherAssets	7000000	USD
CY2013	us-gaap	Increase Decrease In Employee Related Liabilities IncreaseDecreaseInEmployeeRelatedLiabilities	-28000000	USD
CY2014	us-gaap	Increase Decrease In Employee Related Liabilities IncreaseDecreaseInEmployeeRelatedLiabilities	-10000000	USD
CY2015	us-gaap	Increase Decrease In Employee Related Liabilities IncreaseDecreaseInEmployeeRelatedLiabilities	-9000000	USD
CY2013	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	-60000000	USD
CY2014	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	-3000000	USD
CY2015	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	14000000	USD
CY2013	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	-20000000	USD
CY2014	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	-30000000	USD
CY2015	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	-53000000	USD
CY2013	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-14000000	USD
CY2014	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-28000000	USD
CY2015	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-56000000	USD
CY2013	us-gaap	Increase Decrease In Receivables IncreaseDecreaseInReceivables	60000000	USD
CY2014	us-gaap	Increase Decrease In Receivables IncreaseDecreaseInReceivables	-31000000	USD
CY2015	us-gaap	Increase Decrease In Receivables IncreaseDecreaseInReceivables	-83000000	USD
CY2013	us-gaap	Increase Decrease In Regulatory Assets And Liabilities IncreaseDecreaseInRegulatoryAssetsAndLiabilities	-29000000	USD
CY2014	us-gaap	Increase Decrease In Regulatory Assets And Liabilities IncreaseDecreaseInRegulatoryAssetsAndLiabilities	281000000	USD
CY2015	us-gaap	Increase Decrease In Regulatory Assets And Liabilities IncreaseDecreaseInRegulatoryAssetsAndLiabilities	-94000000	USD
CY2013	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	1900000	shares
CY2014	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	1800000	shares
CY2015	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	1000000	shares
CY2013	us-gaap	Interest Expense InterestExpense	398000000	USD
CY2014	us-gaap	Interest Expense InterestExpense	341000000	USD
CY2015	us-gaap	Interest Expense InterestExpense	355000000	USD
CY2013	us-gaap	Interest Income Securities Tax Exempt InterestIncomeSecuritiesTaxExempt	27000000	USD
CY2014	us-gaap	Interest Income Securities Tax Exempt InterestIncomeSecuritiesTaxExempt	27000000	USD
CY2015	us-gaap	Interest Income Securities Tax Exempt InterestIncomeSecuritiesTaxExempt	27000000	USD
CY2013	us-gaap	Interest Paid Capitalized InterestPaidCapitalized	37000000	USD
CY2014	us-gaap	Interest Paid Capitalized InterestPaidCapitalized	18000000	USD
CY2015	us-gaap	Interest Paid Capitalized InterestPaidCapitalized	17000000	USD
CY2013	us-gaap	Interest Paid Net InterestPaidNet	393000000	USD
CY2014	us-gaap	Interest Paid Net InterestPaidNet	333000000	USD
CY2015	us-gaap	Interest Paid Net InterestPaidNet	335000000	USD
CY2014Q4	us-gaap	Interest Payable Current InterestPayableCurrent	85000000	USD
CY2015Q4	us-gaap	Interest Payable Current InterestPayableCurrent	89000000	USD
CY2014Q4	us-gaap	Inventory Net InventoryNet	524000000	USD
CY2015Q4	us-gaap	Inventory Net InventoryNet	538000000	USD
CY2013	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	32000000	USD
CY2014	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	37000000	USD
CY2015	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	36000000	USD
CY2014Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	22289000000	USD
CY2015Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	23640000000	USD
CY2014Q4	us-gaap	Liabilities Current LiabilitiesCurrent	2249000000	USD
CY2015Q4	us-gaap	Liabilities Current LiabilitiesCurrent	2093000000	USD
CY2014Q4	us-gaap	Liabilities Of Disposal Group Including Discontinued Operation Current LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent	33000000	USD
CY2015Q4	us-gaap	Liabilities Of Disposal Group Including Discontinued Operation Current LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent	29000000	USD
CY2014Q4	us-gaap	Liabilities Other Than Longterm Debt Noncurrent LiabilitiesOtherThanLongtermDebtNoncurrent	7100000000	USD
CY2015Q4	us-gaap	Liabilities Other Than Longterm Debt Noncurrent LiabilitiesOtherThanLongtermDebtNoncurrent	7579000000	USD
CY2015Q4	us-gaap	Long Term Debt LongTermDebt	7331000000	USD
CY2014Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	120000000	USD
CY2015Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	395000000	USD
CY2015Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal After Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive	4392000000	USD
CY2015Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Next Twelve Months LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths	395000000	USD
CY2015Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive	442000000	USD
CY2015Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Four LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour	581000000	USD
CY2015Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Three LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree	840000000	USD
CY2015Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Two LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo	681000000	USD
CY2014Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	6085000000	USD
CY2015Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	6880000000	USD
CY2014Q4	us-gaap	Minority Interest MinorityInterest	142000000	USD
CY2015Q4	us-gaap	Minority Interest MinorityInterest	142000000	USD
CY2013	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-149000000	USD
CY2014	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	141000000	USD
CY2015	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	246000000	USD
CY2013	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-1723000000	USD
CY2014	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-1717000000	USD
CY2015	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-1976000000	USD
CY2013	us-gaap	Net Cash Provided By Used In Investing Activities Continuing Operations NetCashProvidedByUsedInInvestingActivitiesContinuingOperations	-1440000000	USD
CY2014	us-gaap	Net Cash Provided By Used In Investing Activities Continuing Operations NetCashProvidedByUsedInInvestingActivitiesContinuingOperations	-1856000000	USD
CY2015	us-gaap	Net Cash Provided By Used In Investing Activities Continuing Operations NetCashProvidedByUsedInInvestingActivitiesContinuingOperations	-1951000000	USD
CY2013	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	1693000000	USD
CY2014	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	1551000000	USD
CY2015	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	2017000000	USD
CY2013	us-gaap	Net Cash Provided By Used In Operating Activities Continuing Operations NetCashProvidedByUsedInOperatingActivitiesContinuingOperations	1636000000	USD
CY2014	us-gaap	Net Cash Provided By Used In Operating Activities Continuing Operations NetCashProvidedByUsedInOperatingActivitiesContinuingOperations	1557000000	USD
CY2015	us-gaap	Net Cash Provided By Used In Operating Activities Continuing Operations NetCashProvidedByUsedInOperatingActivitiesContinuingOperations	2021000000	USD
CY2013	us-gaap	Net Income Loss NetIncomeLoss	289000000	USD
CY2014Q1	us-gaap	Net Income Loss NetIncomeLoss	96000000	USD
CY2014Q2	us-gaap	Net Income Loss NetIncomeLoss	149000000	USD
CY2014Q3	us-gaap	Net Income Loss NetIncomeLoss	293000000	USD
CY2014Q4	us-gaap	Net Income Loss NetIncomeLoss	48000000	USD
CY2014	us-gaap	Net Income Loss NetIncomeLoss	586000000	USD
CY2015Q1	us-gaap	Net Income Loss NetIncomeLoss	108000000	USD
CY2015Q2	us-gaap	Net Income Loss NetIncomeLoss	150000000	USD
CY2015Q3	us-gaap	Net Income Loss NetIncomeLoss	343000000	USD
CY2015Q4	us-gaap	Net Income Loss NetIncomeLoss	29000000	USD
CY2015	us-gaap	Net Income Loss NetIncomeLoss	630000000	USD
CY2015	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	2	segment
CY2013	us-gaap	Operating Expenses OperatingExpenses	4654000000	USD
CY2014	us-gaap	Operating Expenses OperatingExpenses	4799000000	USD
CY2015	us-gaap	Operating Expenses OperatingExpenses	4839000000	USD
CY2013	us-gaap	Operating Income Loss OperatingIncomeLoss	1184000000	USD
CY2014Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	246000000	USD
CY2014Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	322000000	USD
CY2014Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	561000000	USD
CY2014Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	125000000	USD
CY2014	us-gaap	Operating Income Loss OperatingIncomeLoss	1254000000	USD
CY2015Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	256000000	USD
CY2015Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	237000000	USD
CY2015Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	626000000	USD
CY2015Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	140000000	USD
CY2015	us-gaap	Operating Income Loss OperatingIncomeLoss	1259000000	USD
CY2015Q4	us-gaap	Operating Leases Future Minimum Payments Due OperatingLeasesFutureMinimumPaymentsDue	92000000	USD
CY2015Q4	us-gaap	Operating Leases Future Minimum Payments Due Current OperatingLeasesFutureMinimumPaymentsDueCurrent	14000000	USD
CY2015Q4	us-gaap	Operating Leases Future Minimum Payments Due In Five Years OperatingLeasesFutureMinimumPaymentsDueInFiveYears	11000000	USD
CY2015Q4	us-gaap	Operating Leases Future Minimum Payments Due In Four Years OperatingLeasesFutureMinimumPaymentsDueInFourYears	12000000	USD
CY2015Q4	us-gaap	Operating Leases Future Minimum Payments Due In Three Years OperatingLeasesFutureMinimumPaymentsDueInThreeYears	12000000	USD
CY2015Q4	us-gaap	Operating Leases Future Minimum Payments Due In Two Years OperatingLeasesFutureMinimumPaymentsDueInTwoYears	13000000	USD
CY2015Q4	us-gaap	Operating Leases Future Minimum Payments Due Thereafter OperatingLeasesFutureMinimumPaymentsDueThereafter	30000000	USD
CY2014Q4	us-gaap	Operating Loss Carryforwards OperatingLossCarryforwards	531000000	USD
CY2015Q4	us-gaap	Operating Loss Carryforwards OperatingLossCarryforwards	453000000	USD
CY2015	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-20000000	USD
CY2014Q4	us-gaap	Other Assets Current OtherAssetsCurrent	86000000	USD
CY2015Q4	us-gaap	Other Assets Current OtherAssetsCurrent	88000000	USD
CY2014Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	629000000	USD
CY2015Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	575000000	USD
CY2013	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-30000000	USD
CY2014	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	12000000	USD
CY2015	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-6000000	USD
CY2013	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	16000000	USD
CY2014	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	-7000000	USD
CY2015	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	3000000	USD
CY2013	us-gaap	Other Income OtherIncome	2000000	USD
CY2014	us-gaap	Other Income OtherIncome	8000000	USD
CY2015	us-gaap	Other Income OtherIncome	3000000	USD
CY2013	us-gaap	Other Interest And Dividend Income OtherInterestAndDividendIncome	3000000	USD
CY2014	us-gaap	Other Interest And Dividend Income OtherInterestAndDividendIncome	10000000	USD
CY2015	us-gaap	Other Interest And Dividend Income OtherInterestAndDividendIncome	14000000	USD
CY2014Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	434000000	USD
CY2015Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	379000000	USD
CY2014Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	514000000	USD
CY2015Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	531000000	USD
CY2013	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-23000000	USD
CY2014	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	24000000	USD
CY2015	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	10000000	USD
CY2013	us-gaap	Other Noninterest Expense OtherNoninterestExpense	14000000	USD
CY2014	us-gaap	Other Noninterest Expense OtherNoninterestExpense	12000000	USD
CY2015	us-gaap	Other Noninterest Expense OtherNoninterestExpense	15000000	USD
CY2013	us-gaap	Other Nonoperating Expense OtherNonoperatingExpense	26000000	USD
CY2014	us-gaap	Other Nonoperating Expense OtherNonoperatingExpense	22000000	USD
CY2015	us-gaap	Other Nonoperating Expense OtherNonoperatingExpense	30000000	USD
CY2013	us-gaap	Other Nonoperating Income OtherNonoperatingIncome	69000000	USD
CY2014	us-gaap	Other Nonoperating Income OtherNonoperatingIncome	79000000	USD
CY2015	us-gaap	Other Nonoperating Income OtherNonoperatingIncome	74000000	USD
CY2013	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	43000000	USD
CY2014	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	57000000	USD
CY2015	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	44000000	USD
CY2014Q4	us-gaap	Other Receivables Net Current OtherReceivablesNetCurrent	81000000	USD
CY2015Q4	us-gaap	Other Receivables Net Current OtherReceivablesNetCurrent	98000000	USD
CY2013	us-gaap	Payment Of Financing And Stock Issuance Costs PaymentOfFinancingAndStockIssuanceCosts	2000000	USD
CY2014	us-gaap	Payment Of Financing And Stock Issuance Costs PaymentOfFinancingAndStockIssuanceCosts	11000000	USD
CY2015	us-gaap	Payment Of Financing And Stock Issuance Costs PaymentOfFinancingAndStockIssuanceCosts	12000000	USD
CY2013	us-gaap	Payments For Nuclear Fuel PaymentsForNuclearFuel	45000000	USD
CY2014	us-gaap	Payments For Nuclear Fuel PaymentsForNuclearFuel	74000000	USD
CY2015	us-gaap	Payments For Nuclear Fuel PaymentsForNuclearFuel	52000000	USD
CY2013	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-1000000	USD
CY2014	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-11000000	USD
CY2013Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	6686000000	USD
CY2014Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	6855000000	USD
CY2015Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	7088000000	USD
CY2014Q4	us-gaap	Tax Credit Carryforward Amount TaxCreditCarryforwardAmount	131000000	USD
CY2013	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	388000000	USD
CY2014	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	390000000	USD
CY2015	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	402000000	USD
CY2013	us-gaap	Payments Of Dividends Minority Interest PaymentsOfDividendsMinorityInterest	6000000	USD
CY2014	us-gaap	Payments Of Dividends Minority Interest PaymentsOfDividendsMinorityInterest	6000000	USD
CY2015	us-gaap	Payments Of Dividends Minority Interest PaymentsOfDividendsMinorityInterest	6000000	USD
CY2013	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	214000000	USD
CY2014	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	405000000	USD
CY2015	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	363000000	USD
CY2013	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	1379000000	USD
CY2014	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	1785000000	USD
CY2015	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	1917000000	USD
CY2014Q4	us-gaap	Pension And Other Postretirement Defined Benefit Plans Liabilities Current And Noncurrent PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent	710000000	USD
CY2015Q4	us-gaap	Pension And Other Postretirement Defined Benefit Plans Liabilities Current And Noncurrent PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent	567000000	USD
CY2014Q4	us-gaap	Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent	705000000	USD
CY2015Q4	us-gaap	Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent	580000000	USD
CY2015Q4	us-gaap	Preferred Stock Liquidation Preference PreferredStockLiquidationPreference	105.50
CY2015Q4	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0.01
CY2015Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	100000000	shares
CY2015Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	0	shares
CY2013	us-gaap	Proceeds From Collection Of Notes Receivable ProceedsFromCollectionOfNotesReceivable	6000000	USD
CY2014	us-gaap	Proceeds From Collection Of Notes Receivable ProceedsFromCollectionOfNotesReceivable	95000000	USD
CY2015	us-gaap	Proceeds From Collection Of Notes Receivable ProceedsFromCollectionOfNotesReceivable	20000000	USD
CY2013	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	278000000	USD
CY2014	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	898000000	USD
CY2015	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	1197000000	USD
CY2013	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	0	USD
CY2014	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	1000000	USD
CY2015	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	2000000	USD
CY2013	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	368000000	USD
CY2014	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	346000000	USD
CY2015	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	-413000000	USD
CY2013	us-gaap	Proceeds From Sale And Maturity Of Other Investments ProceedsFromSaleAndMaturityOfOtherInvestments	196000000	USD
CY2014	us-gaap	Proceeds From Sale And Maturity Of Other Investments ProceedsFromSaleAndMaturityOfOtherInvestments	391000000	USD
CY2015	us-gaap	Proceeds From Sale And Maturity Of Other Investments ProceedsFromSaleAndMaturityOfOtherInvestments	349000000	USD
CY2013	us-gaap	Profit Loss ProfitLoss	295000000	USD
CY2014Q1	us-gaap	Profit Loss ProfitLoss	98000000	USD
CY2014Q2	us-gaap	Profit Loss ProfitLoss	150000000	USD
CY2014Q3	us-gaap	Profit Loss ProfitLoss	295000000	USD
CY2014Q4	us-gaap	Profit Loss ProfitLoss	49000000	USD
CY2014	us-gaap	Profit Loss ProfitLoss	592000000	USD
CY2015Q1	us-gaap	Profit Loss ProfitLoss	110000000	USD
CY2015Q2	us-gaap	Profit Loss ProfitLoss	151000000	USD
CY2015Q3	us-gaap	Profit Loss ProfitLoss	345000000	USD
CY2015Q4	us-gaap	Profit Loss ProfitLoss	30000000	USD
CY2015	us-gaap	Profit Loss ProfitLoss	636000000	USD
CY2014Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	26198000000	USD
CY2015Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	27603000000	USD
CY2014Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	17424000000	USD
CY2015Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	18799000000	USD
CY2013	us-gaap	Public Utilities Allowance For Funds Used During Construction Capitalized Cost Of Equity PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity	37000000	USD
CY2014	us-gaap	Public Utilities Allowance For Funds Used During Construction Capitalized Cost Of Equity PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity	34000000	USD
CY2015	us-gaap	Public Utilities Allowance For Funds Used During Construction Capitalized Cost Of Equity PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity	30000000	USD
CY2014Q4	us-gaap	Public Utilities Inventory PublicUtilitiesInventory	263000000	USD
CY2015Q4	us-gaap	Public Utilities Inventory PublicUtilitiesInventory	268000000	USD
CY2014Q4	us-gaap	Regulated Entity Other Assets Noncurrent RegulatedEntityOtherAssetsNoncurrent	3171000000	USD
CY2015Q4	us-gaap	Regulated Entity Other Assets Noncurrent RegulatedEntityOtherAssetsNoncurrent	2924000000	USD
CY2014Q4	us-gaap	Regulatory Assets Current RegulatoryAssetsCurrent	295000000	USD
CY2015Q4	us-gaap	Regulatory Assets Current RegulatoryAssetsCurrent	260000000	USD
CY2014Q4	us-gaap	Regulatory Assets Noncurrent RegulatoryAssetsNoncurrent	1582000000	USD
CY2015Q4	us-gaap	Regulatory Assets Noncurrent RegulatoryAssetsNoncurrent	1382000000	USD
CY2014Q4	us-gaap	Regulatory Liability Current RegulatoryLiabilityCurrent	106000000	USD
CY2015Q4	us-gaap	Regulatory Liability Current RegulatoryLiabilityCurrent	80000000	USD
CY2014Q4	us-gaap	Regulatory Liability Noncurrent RegulatoryLiabilityNoncurrent	1850000000	USD
CY2015Q4	us-gaap	Regulatory Liability Noncurrent RegulatoryLiabilityNoncurrent	1905000000	USD
CY2013	us-gaap	Repayments Of Other Long Term Debt RepaymentsOfOtherLongTermDebt	399000000	USD
CY2014	us-gaap	Repayments Of Other Long Term Debt RepaymentsOfOtherLongTermDebt	697000000	USD
CY2015	us-gaap	Repayments Of Other Long Term Debt RepaymentsOfOtherLongTermDebt	120000000	USD
CY2014Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	1103000000	USD
CY2015Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	1331000000	USD
CY2013	us-gaap	Revenues Revenues	5838000000	USD
CY2014Q1	us-gaap	Revenues Revenues	1594000000	USD
CY2014Q2	us-gaap	Revenues Revenues	1419000000	USD
CY2014Q3	us-gaap	Revenues Revenues	1670000000	USD
CY2014Q4	us-gaap	Revenues Revenues	1370000000	USD
CY2014	us-gaap	Revenues Revenues	6053000000	USD
CY2015Q1	us-gaap	Revenues Revenues	1556000000	USD
CY2015Q2	us-gaap	Revenues Revenues	1401000000	USD
CY2015Q3	us-gaap	Revenues Revenues	1833000000	USD
CY2015Q4	us-gaap	Revenues Revenues	1308000000	USD
CY2015	us-gaap	Revenues Revenues	6098000000	USD
CY2013	us-gaap	Share Based Compensation ShareBasedCompensation	27000000	USD
CY2014	us-gaap	Share Based Compensation ShareBasedCompensation	25000000	USD
CY2015	us-gaap	Share Based Compensation ShareBasedCompensation	24000000	USD
CY2015Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant	8000000	shares
CY2014Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	714000000	USD
CY2015Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	301000000	USD
CY2014Q4	us-gaap	Stockholders Equity StockholdersEquity	6713000000	USD
CY2015Q4	us-gaap	Stockholders Equity StockholdersEquity	6946000000	USD
CY2015Q4	us-gaap	Tax Credit Carryforward Amount TaxCreditCarryforwardAmount	144000000	USD
CY2014	us-gaap	Tax Credit Carryforward Expiration Date TaxCreditCarryforwardExpirationDate	2013-01-01
CY2015	us-gaap	Tax Credit Carryforward Expiration Date TaxCreditCarryforwardExpirationDate	2016-01-01
CY2013	us-gaap	Taxes Excluding Income And Excise Taxes TaxesExcludingIncomeAndExciseTaxes	458000000	USD
CY2014	us-gaap	Taxes Excluding Income And Excise Taxes TaxesExcludingIncomeAndExciseTaxes	468000000	USD
CY2015	us-gaap	Taxes Excluding Income And Excise Taxes TaxesExcludingIncomeAndExciseTaxes	473000000	USD
CY2014Q4	us-gaap	Taxes Payable Current TaxesPayableCurrent	46000000	USD
CY2015Q4	us-gaap	Taxes Payable Current TaxesPayableCurrent	43000000	USD
CY2014Q4	us-gaap	Unbilled Receivables Current UnbilledReceivablesCurrent	265000000	USD
CY2015Q4	us-gaap	Unbilled Receivables Current UnbilledReceivablesCurrent	239000000	USD
CY2012Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	156000000	USD
CY2013Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	90000000	USD
CY2014Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	54000000	USD
CY2015Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	0	USD
CY2013	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromCurrentPeriodTaxPositions	103000000	USD
CY2013	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	143000000	USD
CY2014	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	42000000	USD
CY2015	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	56000000	USD
CY2013	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	69000000	USD
CY2015	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	0	USD
CY2013	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	7000000	USD
CY2014	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	6000000	USD
CY2015	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	2000000	USD
CY2012Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	6000000	USD
CY2013Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	1000000	USD
CY2014Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	0	USD
CY2015Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	0	USD
CY2013	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Expense UnrecognizedTaxBenefitsInterestOnIncomeTaxesExpense	5000000	USD
CY2014	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Expense UnrecognizedTaxBenefitsInterestOnIncomeTaxesExpense	1000000	USD
CY2013	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	-1000000	USD
CY2013Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	54000000	USD
CY2014Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	52000000	USD
CY2015Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	0	USD
CY2015Q4	us-gaap	Unrecorded Unconditional Purchase Obligation Balance On Fifth Anniversary UnrecordedUnconditionalPurchaseObligationBalanceOnFifthAnniversary	215000000	USD
CY2015Q4	us-gaap	Unrecorded Unconditional Purchase Obligation Balance On First Anniversary UnrecordedUnconditionalPurchaseObligationBalanceOnFirstAnniversary	1323000000	USD
CY2015Q4	us-gaap	Unrecorded Unconditional Purchase Obligation Balance On Fourth Anniversary UnrecordedUnconditionalPurchaseObligationBalanceOnFourthAnniversary	342000000	USD
CY2015Q4	us-gaap	Unrecorded Unconditional Purchase Obligation Balance On Second Anniversary UnrecordedUnconditionalPurchaseObligationBalanceOnSecondAnniversary	1145000000	USD
CY2015Q4	us-gaap	Unrecorded Unconditional Purchase Obligation Balance On Third Anniversary UnrecordedUnconditionalPurchaseObligationBalanceOnThirdAnniversary	531000000	USD
CY2015Q4	us-gaap	Unrecorded Unconditional Purchase Obligation Balance Sheet Amount UnrecordedUnconditionalPurchaseObligationBalanceSheetAmount	4684000000	USD
CY2015Q4	us-gaap	Unrecorded Unconditional Purchase Obligation Due After Five Years UnrecordedUnconditionalPurchaseObligationDueAfterFiveYears	1128000000	USD
CY2013	us-gaap	Utilities Operating Expense Maintenance Operations And Other Costs And Expenses UtilitiesOperatingExpenseMaintenanceOperationsAndOtherCostsAndExpenses	1611000000	USD
CY2014	us-gaap	Utilities Operating Expense Maintenance Operations And Other Costs And Expenses UtilitiesOperatingExpenseMaintenanceOperationsAndOtherCostsAndExpenses	1684000000	USD
CY2015	us-gaap	Utilities Operating Expense Maintenance Operations And Other Costs And Expenses UtilitiesOperatingExpenseMaintenanceOperationsAndOtherCostsAndExpenses	1694000000	USD
CY2013	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	244500000	shares
CY2014	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	244400000	shares
CY2015	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	243600000	shares
CY2013	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	242600000	shares
CY2014	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	242600000	shares
CY2015	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	242600000	shares
CY2015	aee	Disclosure Of Accrued Capital Expenditures Excluded From Statements Of Cash Flow DisclosureOfAccruedCapitalExpendituresExcludedFromStatementsOfCashFlow	<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;padding-left:4px;padding-top:13px;text-align:left;text-indent:24px;font-size:10pt;"><font style="font-family:Arial Narrow;font-size:10pt;">The following table provides accrued capital and nuclear fuel expenditures at </font><font style="font-family:Arial Narrow;font-size:10pt;color:#000000;text-decoration:none;">December 31, 2015</font><font style="font-family:Arial Narrow;font-size:10pt;">, </font><font style="font-family:Arial Narrow;font-size:10pt;color:#000000;text-decoration:none;">2014</font><font style="font-family:Arial Narrow;font-size:10pt;">, and </font><font style="font-family:Arial Narrow;font-size:10pt;color:#000000;text-decoration:none;">2013</font><font style="font-family:Arial Narrow;font-size:10pt;">, which represent noncash investing activity excluded from the accompanying statements of cash flows:</font></div><div style="line-height:100%;font-size:10pt;"><div style="padding-left:0px;text-indent:0px;line-height:normal;padding-top:10px;"><table cellpadding="0" cellspacing="0" style="font-family:Times New Roman;font-size:10pt;width:100%;border-collapse:collapse;text-align:left;"><tr><td colspan="12" rowspan="1"></td></tr><tr><td width="59%" rowspan="1" colspan="1"></td><td width="1%" rowspan="1" colspan="1"></td><td width="11%" rowspan="1" colspan="1"></td><td width="1%" rowspan="1" colspan="1"></td><td width="1%" rowspan="1" colspan="1"></td><td width="1%" rowspan="1" colspan="1"></td><td width="11%" rowspan="1" colspan="1"></td><td width="1%" rowspan="1" colspan="1"></td><td width="1%" rowspan="1" colspan="1"></td><td width="1%" rowspan="1" colspan="1"></td><td width="11%" rowspan="1" colspan="1"></td><td width="1%" rowspan="1" colspan="1"></td></tr><tr><td style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;border-top:2px solid #000000;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;border-top:2px solid #000000;" rowspan="1"><div style="text-align:center;font-size:10pt;"><font style="font-family:Arial Narrow;font-size:8pt;font-weight:bold;">Ameren</font><font style="font-family:Arial Narrow;font-size:10pt;font-weight:bold;"><sup style="vertical-align:top;line-height:120%;font-size:6pt">(a)</sup></font></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;border-top:2px solid #000000;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;border-top:2px solid #000000;" rowspan="1"><div style="text-align:center;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;font-weight:bold;">Ameren</font></div><div style="text-align:center;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;font-weight:bold;">Missouri</font></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;border-top:2px solid #000000;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;border-top:2px solid #000000;" rowspan="1"><div style="text-align:center;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;font-weight:bold;">Ameren</font></div><div style="text-align:center;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;font-weight:bold;">Illinois</font></div></td></tr><tr><td style="vertical-align:top;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;">Accrued capital expenditures:</font></div></td><td colspan="3" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td></tr><tr><td style="vertical-align:top;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;">2015</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;font-weight:bold;">$</font></div></td><td style="vertical-align:bottom;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;font-weight:bold;">235</font></div></td><td style="vertical-align:bottom;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;font-weight:bold;">$</font></div></td><td style="vertical-align:bottom;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;font-weight:bold;">85</font></div></td><td style="vertical-align:bottom;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;font-weight:bold;">$</font></div></td><td style="vertical-align:bottom;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;font-weight:bold;">92</font></div></td><td style="vertical-align:bottom;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td></tr><tr><td style="vertical-align:top;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;">2014</font></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"><div style="text-align:right;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;">181</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"><div style="text-align:right;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;">72</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"><div style="text-align:right;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;">59</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td></tr><tr><td style="vertical-align:top;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;">2013</font></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"><div style="text-align:right;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;">175</font></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"><div style="text-align:right;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;">74</font></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"><div style="text-align:right;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;">86</font></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td></tr><tr><td style="vertical-align:top;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;">Accrued nuclear fuel expenditures:</font></div></td><td colspan="3" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td></tr><tr><td style="vertical-align:top;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;">2015</font></div></td><td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"><div style="text-align:right;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;font-weight:bold;">16</font></div></td><td style="vertical-align:bottom;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"><div style="text-align:right;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;font-weight:bold;">16</font></div></td><td style="vertical-align:bottom;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"><div style="text-align:right;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;font-weight:bold;">(b)</font></div></td><td style="vertical-align:bottom;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td></tr><tr><td style="vertical-align:top;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;">2014</font></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"><div style="text-align:right;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;">13</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"><div style="text-align:right;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;">13</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"><div style="text-align:right;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;">(b)</font></div></td><td style="vertical-align:bottom;background-color:#cceeff;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td></tr><tr><td style="vertical-align:top;border-bottom:2px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;">2013</font></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:2px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"><div style="text-align:right;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;">8</font></div></td><td style="vertical-align:bottom;border-bottom:2px solid #000000;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;border-bottom:2px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:2px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"><div style="text-align:right;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;">8</font></div></td><td style="vertical-align:bottom;border-bottom:2px solid #000000;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;border-bottom:2px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="2" style="vertical-align:bottom;border-bottom:2px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"><div style="text-align:right;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;">(b)</font></div></td><td style="vertical-align:bottom;border-bottom:2px solid #000000;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td></tr></table></div><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><table cellpadding="0" cellspacing="0" style="padding-top:5px;font-family:Times New Roman; font-size:10pt;"><tr><td style="width:24px;" rowspan="1" colspan="1"></td><td rowspan="1" colspan="1"></td></tr><tr><td style="vertical-align:top" rowspan="1" colspan="1"><div style="line-height:120%;font-size:8pt;padding-left:0px;"><font style="font-family:Arial Narrow;font-size:8pt;">(a)</font></div></td><td style="vertical-align:top;" rowspan="1" colspan="1"><div style="line-height:120%;text-align:left;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;">Includes amounts for Ameren registrant and nonregistrant subsidiaries.</font></div></td></tr></table><table cellpadding="0" cellspacing="0" style="padding-bottom:13px;font-family:Times New Roman; font-size:10pt;"><tr><td style="width:24px;" rowspan="1" colspan="1"></td><td rowspan="1" colspan="1"></td></tr><tr><td style="vertical-align:top" rowspan="1" colspan="1"><div style="line-height:120%;font-size:8pt;padding-left:0px;"><font style="font-family:Arial Narrow;font-size:8pt;">(b)</font></div></td><td style="vertical-align:top;" rowspan="1" colspan="1"><div style="line-height:120%;text-align:left;font-size:8pt;"><font style="font-family:Arial Narrow;font-size:8pt;">Not applicable.</font></div></td></tr></table></div>
CY2015	us-gaap	Nature Of Operations NatureOfOperations	<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;padding-top:13px;text-indent:24px;font-size:10pt;"><font style="font-family:Arial Narrow;font-size:10pt;">Ameren, headquartered in St. Louis, Missouri, is a public utility holding company under PUHCA 2005. Ameren’s primary assets are its equity interests in its subsidiaries, including Ameren Missouri and Ameren Illinois. Ameren’s subsidiaries are separate, independent legal entities with separate businesses, assets, and liabilities. Dividends on Ameren’s common stock and the payment of expenses by Ameren depend on distributions made to it by its subsidiaries. Ameren’s principal subsidiaries are listed below. </font></div><table cellpadding="0" cellspacing="0" style="padding-top:13px;font-family:Times New Roman; font-size:10pt;"><tr><td style="width:24px;" rowspan="1" colspan="1"></td><td rowspan="1" colspan="1"></td></tr><tr><td style="vertical-align:top" rowspan="1" colspan="1"><div style="line-height:120%;font-size:10pt;padding-left:0px;"><font style="font-family:Arial Narrow;font-size:10pt;">•</font></div></td><td style="vertical-align:top;" rowspan="1" colspan="1"><div style="line-height:120%;font-size:10pt;"><font style="font-family:Arial Narrow;font-size:10pt;">Union Electric Company, doing business as Ameren Missouri, operates a rate-regulated electric generation, transmission, and distribution business and a rate-regulated natural gas transmission and distribution business in Missouri. Ameren Missouri was incorporated in Missouri in 1922 and is successor to a number of companies, the oldest of which was organized in 1881. It is the largest electric utility in the state of Missouri. It supplies electric and natural gas service to a </font><font style="font-family:Arial Narrow;font-size:10pt;color:#000000;text-decoration:none;">24,000</font><font style="font-family:Arial Narrow;font-size:10pt;">-square-mile area in central and eastern Missouri. This area has an estimated population of </font><font style="font-family:Arial Narrow;font-size:10pt;color:#000000;text-decoration:none;">2.8 million</font><font style="font-family:Arial Narrow;font-size:10pt;"> and includes the Greater St. Louis area. Ameren Missouri supplies electric service to </font><font style="font-family:Arial Narrow;font-size:10pt;color:#000000;text-decoration:none;">1.2 million</font><font style="font-family:Arial Narrow;font-size:10pt;"> customers and natural gas service to </font><font style="font-family:Arial Narrow;font-size:10pt;">0.1 million</font><font style="font-family:Arial Narrow;font-size:10pt;"> customers.</font></div></td></tr></table><table cellpadding="0" cellspacing="0" style="font-family:Times New Roman; font-size:10pt;"><tr><td style="width:24px;" rowspan="1" colspan="1"></td><td rowspan="1" colspan="1"></td></tr><tr><td style="vertical-align:top" rowspan="1" colspan="1"><div style="line-height:120%;font-size:10pt;padding-left:0px;"><font style="font-family:Arial Narrow;font-size:10pt;">•</font></div></td><td style="vertical-align:top;" rowspan="1" colspan="1"><div style="line-height:120%;font-size:10pt;"><font style="font-family:Arial Narrow;font-size:10pt;">Ameren Illinois Company, doing business as Ameren Illinois, operates rate-regulated electric and natural gas transmission and distribution businesses in Illinois. Ameren Illinois was created by the merger of CILCO and IP with and into CIPS in 2010. CIPS was incorporated in Illinois in 1923 and was the successor to a number of companies, the oldest of which was organized in 1902. Ameren Illinois supplies electric and natural gas utility service to portions of central and southern Illinois having an estimated population of </font><font style="font-family:Arial Narrow;font-size:10pt;color:#000000;text-decoration:none;">3.1 million</font><font style="font-family:Arial Narrow;font-size:10pt;"> in an area of </font><font style="font-family:Arial Narrow;font-size:10pt;color:#000000;text-decoration:none;">40,000</font><font style="font-family:Arial Narrow;font-size:10pt;"> square miles. Ameren Illinois supplies electric service to </font><font style="font-family:Arial Narrow;font-size:10pt;color:#000000;text-decoration:none;">1.2 million</font><font style="font-family:Arial Narrow;font-size:10pt;"> customers and natural gas service to </font><font style="font-family:Arial Narrow;font-size:10pt;">0.8 million</font><font style="font-family:Arial Narrow;font-size:10pt;"> customers.</font></div></td></tr></table><div style="line-height:120%;padding-top:13px;text-indent:24px;font-size:10pt;"><font style="font-family:Arial Narrow;font-size:10pt;">Ameren has various other subsidiaries that conduct activities such as the provision of shared services. Ameren also has a subsidiary, ATXI, that operates a FERC rate-regulated electric transmission business. ATXI is developing MISO-approved electric transmission projects, including the Illinois Rivers, Spoon River, and Mark Twain projects. Ameren is also pursuing projects to improve electric transmission system reliability within Ameren Missouri's and Ameren Illinois' service territories as well as competitive electric transmission investment opportunities outside of these territories, including investments outside of MISO.</font></div><div style="line-height:120%;padding-top:13px;text-align:left;text-indent:24px;font-size:10pt;"><font style="font-family:Arial Narrow;font-size:10pt;"></font></div></div>

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$AEE
AMEREN CORP Stock $aee

2015 Q4 Form 10-K Financial Statement

#000100291016000205 Filed on February 26, 2016

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$AEE AMEREN CORP Stock $aee

2015 Q4 Form 10-K Financial Statement

#000100291016000205 Filed on February 26, 2016

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$AEE
AMEREN CORP Stock $aee