CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Statement of Comprehensive Income [Abstract]
Net Income (Loss)	$ 2,445		$ (2,568)		$ 821
Other Comprehensive Income (Loss), net of taxes
Reclassification of previously deferred derivative losses to net income	8	[1]	10	[1]	17	[1]
Adjustments for pension and other postretirement plans
Net gain (loss) incurred during period	(99)	[2]	(136)	[2]	(91)	[2]
Prior service credit (cost) incurred during period			7	[3]	(4)	[3]
Amortization of net actuarial loss and prior service cost to net periodic benefit cost	63	[4]	56	[4]	41	[4]
Total adjustments for pension and other postretirement plans	(36)		(73)		(54)
Total	(28)		(63)		(37)
Comprehensive Income (Loss)	2,417		(2,631)		784
Comprehensive Income Attributable to Noncontrolling Interests	54		81		60
Comprehensive Income (Loss) Attributable to Common Stockholders	$ 2,363		$ (2,712)		$ 724

[1] Net of income tax benefit (expense) of $(4) million in 2012, $(5) million in 2011, and $(9) million in 2010.

[2] Net of income tax benefit (expense) of $56 million in 2012, $77 million in 2011, and $52 million in 2010.

[3] Net of income tax benefit (expense) of $(5) million in 2011 and $2 million in 2010.

[4] Net of income tax benefit (expense) of $(32) million in 2012, $(31) million in 2011, and $(23) million in 2010.