CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement of Comprehensive Income [Abstract]
Net income	$ 143	$ 73	$ 247	$ 34
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	21	19	(31)	18
Fixed price diesel swaps	0	2	0	1
Other comprehensive income (loss)	21	21	(31)	19
Comprehensive income	$ 164	$ 94	$ 216	$ 53