Consolidated Statements of Income (Parenthetical) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Consolidated Statements of Income [Abstract]
Earnings allocated to participating share awards and other items.	$ (15)	$ (13)	$ (44)	$ (38)