CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (LOSS) (UNAUDITED) - 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)	$ (216)	$ 229	$ (221)	$ 335
Net change in unrealized gains (losses), net of tax, on:
Derivatives designated as cash flow hedges	9	9	20	23
Other comprehensive income, net of tax	9	9	20	23
Total comprehensive income (loss)	$ (207)	$ 238	$ (201)	$ 358