CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Paranthetical) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Expense (Benefit)	$ 26	$ 28	$ 24
Other Comprehensive Income, Finalization of Pension [Member]
Income Tax Expense (Benefit)	5	0	0
Pension Plans, Defined Benefit [Member]
Income Tax Expense (Benefit)	0	(5)	(1)
Derivative [Member]
Income Tax Expense (Benefit)	$ (1)	$ 1	$ 0