Equity (Common Stock and Class B Stock Changes in Number of Shares Issued, Held in Treasury and Outstanding) (Parenthetical) (Details) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended		12 Months Ended
	Nov. 30, 2010	Jun. 30, 2009	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Equity
Common Stock issued	18,348,624	36,858,975
Price Per Share	$ 54.50	$ 39.00
Net Proceeds	$ 970	$ 1,391	$ 0	$ 970	$ 1,391