Schedule I Condensed Financial Information Parent Company Statements of Cash Flows (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Financial Statements [Line Items]
Total Cash Flows from Operating Activities	$ 340	$ 938	$ 1,038
Cash Flows from Investing Activities:
Capital Expenditures	(923)	(1,168)	(1,127)
Asset Dispositions	18	25	16
Decrease (Increase) in Restricted Cash	5	14	11
Capital Contributions Received and Loans Incurred	0	0	0
Capital Redemptions and Loans Paid	0	0	0
Other Transactions	26	9	6
Total Cash Flows from Investing Activities	(851)	(1,136)	(1,123)
Cash Flows from Financing Activities:
Short Term Debt and Overdrafts Incurred	46	31	77
Short Term Debt and Overdrafts Paid	(24)	(120)	(156)
Long Term Debt Incurred	1,842	1,913	3,531
Long Term Debt Paid	(1,555)	(681)	(3,717)
Common Stock Issued	39	26	3
Common Stock Repurchased	(234.0)	(4.0)	0
Common Stock Dividends Paid	(60)	(12)	0
Preferred Stock Dividends Paid	(15)	(29)	(29)
Capital Contributions Received and Loans Incurred	0	0	0
Capital Redemptions and Loans Paid	0	0	0
Transactions with Minority Interests in Subsidiaries	(49)	(26)	(71)
Debt Related Costs and Other Transactions	(1)	(16)	(64)
Total Cash Flows from Financing Activities	(11)	1,082	(426)
Net Change in Cash and Cash Equivalents	(835)	715	(491)
Cash and Cash Equivalents at Beginning of the Year	2,996	2,281	2,772
Cash and Cash Equivalents at End of the Year	2,161	2,996	2,281
Parent Company
Condensed Financial Statements [Line Items]
Total Cash Flows from Operating Activities	(334)	17	335
Cash Flows from Investing Activities:
Capital Expenditures	(303)	(220)	(231)
Asset Dispositions	9	2	5
Decrease (Increase) in Restricted Cash	(1)	0	1
Capital Contributions Received and Loans Incurred	(382)	(91)	(191)
Capital Redemptions and Loans Paid	459	214	81
Other Transactions	13	0	4
Total Cash Flows from Investing Activities	(205)	(95)	(331)
Cash Flows from Financing Activities:
Short Term Debt and Overdrafts Incurred	22	14	0
Short Term Debt and Overdrafts Paid	(14)	(90)	0
Long Term Debt Incurred	601	900	800
Long Term Debt Paid	(608)	(11)	(762)
Common Stock Issued	39	26	3
Common Stock Repurchased	(234.0)	(4.0)	0
Common Stock Dividends Paid	(60)	(12)	0
Preferred Stock Dividends Paid	(15)	(29)	(29)
Capital Contributions Received and Loans Incurred	457	170	150
Capital Redemptions and Loans Paid	(244)	(403)	(200)
Transactions with Minority Interests in Subsidiaries	0	0	(17)
Debt Related Costs and Other Transactions	0	(16)	(63)
Total Cash Flows from Financing Activities	(56)	545	(118)
Net Change in Cash and Cash Equivalents	(595)	467	(114)
Cash and Cash Equivalents at Beginning of the Year	1,269	802	916
Cash and Cash Equivalents at End of the Year	$ 674	$ 1,269	$ 802