STATEMENTS OF CONSOLIDATED COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (912)	$ 323	$ 64
Other comprehensive income (loss), net of tax:
Adjustment to postretirement and other postemployment plans (net of tax of $6, $1 and $6)	8	(4)	6
Other comprehensive income (loss)	8	(4)	6
Comprehensive income (loss)	$ (904)	$ 319	$ 70