Consolidated Statements Of Comprehensive (Loss) Income (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Statement Of Income And Comprehensive Income [Abstract]
Net (Loss) Income	$ (430)	$ 68
Other Comprehensive Income from Continuing Operations
Losses on commodity derivatives designated as cash flow hedges reclassified into income	3	7
Pension and other postretirement benefit plans	2	1
Other comprehensive income, before income taxes	5	8
Income tax expense related to other comprehensive income	2	3
Other comprehensive income from continuing operations, net of income taxes	3	5
Other Comprehensive Income from Discontinued Operations, Net of Income Taxes	3	3
Comprehensive (Loss) Income	$ (424)	$ 76