Summary of Significant Accounting Policies (Basic EPS Calculation for Continuing Operations) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income from continuing operations	$ 982	$ 565	$ 531
Less: Net income attributable to non-controlling interests	22	16	14
Net income attributable to the Company	993	855	227
Basic weighted average common shares outstanding	542	540	522
Segment, Continuing Operations [Member]
Income from continuing operations	982	565	531
Less: Net income attributable to non-controlling interests	22	16	14
Net income attributable to the Company	960	549	517
Less: Portion attributable to participating securities	6	6	12
Net income attributable to common shares for basic earnings per shares	$ 954	$ 543	$ 505
Basic weighted average common shares outstanding	542	540	522