Stockholders' Equity (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		1 Months Ended	6 Months Ended	132 Months Ended	1 Months Ended	14 Months Ended
	Jun. 30, 2012	Mar. 31, 2012	Jun. 30, 2001 June 2001 Buyback Plan [Member]	Jun. 30, 2011 June 2001 Buyback Plan [Member]	Jun. 30, 2012 June 2001 Buyback Plan [Member]	Apr. 30, 2011 April 2011 Buyback Plan [Member]	Jun. 30, 2012 April 2011 Buyback Plan [Member]
Prepayment for the repurchase of common stock		$ 400
Stock Repurchase Program, Authorized Amount			2,000			2,000
Stock Repurchased and Retired During Period, Shares	7.8			5.0	42.0		5.5
Stock Repurchased and Retired During Period, Value				$ 272			$ 284