Income Taxes Components of Net Deferred Income Tax Liability (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Deferred income tax assets: [Abstract]
Federal and state carryforwards	$ 1,001	$ 496
Regulatory liabilities	825	736
AROs	234	192
Employee benefits	75	317
Derivative contracts	28	78
Other	740	441
Total deferred income tax assets	2,903	2,260
Valuation allowances	(29)	(16)
Total deferred income tax assets, net	2,874	2,244
Deferred income tax liabilities: [ Abstract]
Property related items	(10,727)	(8,366)
Regulatory assets	(1,047)	(1,093)
Investments	(767)	(351)
Other	(287)	(226)
Total deferred income tax liabilities	(12,828)	(10,036)
Net deferred income tax liability	(9,954)	(7,792)
Reflected as: [Abstract]
Current assets - other	211	119
Current liabilities - other	(7)	(8)
Deferred income taxes	$ (10,158)	$ (7,903)