Derivatives And Hedging Activities (Outstanding Derivative Balances) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Other Current Assets [Member]
Derivatives And Hedging Activities [Line Items]
Gross Derivative Balance	$ 73	$ 42
Cash Collateral	19	16
Total Derivative Balances	88	48
Derivative Liability Offsetting Derivative Asset	(4)	(10)
Other Noncurrent Assets [Member]
Derivatives And Hedging Activities [Line Items]
Gross Derivative Balance	178	99
Cash Collateral	0	0
Total Derivative Balances	165	95
Derivative Liability Offsetting Derivative Asset	(13)	(4)
Other Current Liabilities [Member]
Derivatives And Hedging Activities [Line Items]
Gross Derivative Balance	(78)	(122)
Cash Collateral	26	69
Total Derivative Balances	(48)	(43)
Derivative Asset Offsetting Derivative Liability	4	10
Other Noncurrent Liabilities [Member]
Derivatives And Hedging Activities [Line Items]
Gross Derivative Balance	(140)	(110)
Cash Collateral	9	2
Total Derivative Balances	(118)	(104)
Derivative Asset Offsetting Derivative Liability	13	4
Gross Derivative Balance [Member]
Derivatives And Hedging Activities [Line Items]
Total Gross Derivative Balance	33	(91)
Netting [Member]
Derivatives And Hedging Activities [Line Items]
Derivative Asset Offsetting Derivative Liability	0	0
Cash Collatera [lMember]
Derivatives And Hedging Activities [Line Items]
Cash Collateral	54	87
Total Derivatve Balance [Member]
Derivatives And Hedging Activities [Line Items]
Total Derivative Balances	$ 87	$ (4)