Background And Basis Of Presentation (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	0 Months Ended	1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Oct. 23, 2012	Oct. 31, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Dec. 31, 2011
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Equity method investment, ownership percentage			27.00%		27.00%		27.00%
Planned share repurchase program		$ 1,000,000,000
Common Stock Repurchase Expanded Amount Authorized	1,500,000,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	550,000,000
Repurchase Program Expected Completion Date							Jun. 30, 2013
Shares repurchased during period			7.7		19.6		31.4
Shares repurchased during period, value			$ 262,000,000		$ 622,000,000		$ 950,000,000	$ 1,327,000,000
Average price of repurchased shares, per share			$ 34.25		$ 31.76		$ 30.29
Increase In Quarterly Dividend			7.30%		7.30%		7.30%
Cash Dividends declared			$ 0.44	$ 0.41	$ 1.26	$ 1.17		$ 1.58
Annualized Dividend Rate			$ 1.76		$ 1.76		$ 1.76