CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Statement of Comprehensive Income [Abstract]
Net Income (Loss)	$ 108	$ 266	$ (3,128)	$ (2,360)
Adjustments for derivative instruments
Reclassification of previously deferred derivative losses to (gains) losses on derivatives, net	3	3	5	5
Income taxes on reclassification of previously deferred derivative losses to (gains) losses on derivatives, net	(1)	(1)	(2)	(2)
Total adjustments for derivative instruments, net of taxes	2	2	3	3
Adjustments for pension and other postretirement plans
Amortization of net actuarial (gain) loss to general and administrative expense	13	7	26	14
Income taxes on amortization of net actuarial (gain) loss to general and administrative expense	(5)	(3)	(9)	(5)
Amortization of net prior service (credit) cost to general and administrative expense	1	0	1	0
Total adjustments for pension and other postretirement plans, net of taxes	9	4	18	9
Total	11	6	21	12
Comprehensive Income (Loss)	119	272	(3,107)	(2,348)
Comprehensive income attributable to noncontrolling interests	47	39	79	82
Comprehensive Income (Loss) Attributable to Common Stockholders	$ 72	$ 233	$ (3,186)	$ (2,430)