Shareholders Equity Shareholders Equity (Details 2) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012
Treasury Stock [Roll Forward]
Treasury Stock, Shares, Beginning (in shares)	15,508
Treasury Stock, Value, Beginning	$ 124
Treasury Stock, Shares, Acquired	6,100	[1]
Treasury Stock, Value, Acquired, Cost Method	50	[1]
Treasury Stock, Shares, Retired	(21,197)
Treasury Stock, Retired, Cost Method, Amount	0
Treasury Stock, Shares, Ending (in shares)	411
Treasury Stock, Value, Ending	3
Treasury Stock [Member]
Treasury Stock [Roll Forward]
Treasury Stock, Value, Acquired, Cost Method	50
Treasury Stock, Retired, Cost Method, Amount	$ 171

[1] (1)Includes associated fees.