CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Statement of Other Comprehensive Income [Abstract]
Gain (loss) on derivative instruments, income taxes	$ 1	$ 44	$ 1	$ 133
Reclassification of gain on settled derivative instruments, income taxes	(3)	(49)	(10)	(88)
Ineffective portion of derivatives designated as cash flow hedges income taxes	0	2	0	(5)
Unrealized gain (loss) on available-for-sale securities, income taxes	$ (2)	$ (1)	$ (4)	$ (2)