CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Statement of Comprehensive Income
Reclassification of previously deferred derivative losses to net income, income tax benefit (expense)	$ (1)	$ (2)	$ (4)	$ (7)
Net gain (loss) incurred during period, income tax benefit (expense)				12
Prior service credit (cost) incurred during period, income tax benefit (expense)				2
Amortization of net actuarial loss and prior service cost to net periodic benefit cost, income tax benefit (expense)	$ (8)	$ (5)	$ (24)	$ (17)