Summary of Significant Accounting Policies (Basic EPS Calculation for Net Income) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Net income attributable to the Company	$ 993	$ 855	$ 227
Basic weighted average common shares outstanding	542	540	522
Net Income [Member]
Net income attributable to the Company	993	855	227
Less: Portion attributable to participating securities	6	11	4
Net income attributable to common shares for basic earnings per shares	$ 987	$ 844	$ 223
Basic weighted average common shares outstanding	542	540	522