CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Unrealized gain on derivative instruments, net of income tax expense of $1 million, $4 million and $137 million	$ 1	$ 4	$ 137
Reclassification of (gain) loss on settled derivative instruments, net of income tax expense (benefit) of $12 million, ($10) million and ($139) million	12	(10)	(139)
Ineffective portion of derivatives designated as cash flow hedges, net of income tax expense of $0, $0 and $3 million	0	0	3
Unrealized loss on investments, net of income tax benefit of ($4) million, ($4) million and ($1) million	(4)	(4)	(1)
Reclassification of (gain) loss on investment, net of income tax expense (benefit) of $3 million, $0 and $0	$ 3	$ 0	$ 0