Stockholders' Equity 2 (Details) (USD $)	2 Months Ended	3 Months Ended		9 Months Ended
	Dec. 31, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2012
Stock Repurchase Program [Line Items]
Accelerated share repurchase, value			$ 500,000,000
Stockholders' Equity (Textual) [Abstract]
Number of initial shares received under accelerated share repurchase agreement			15,000,000
Number of additional shares received under accelerated share repurchase agreement		3,700,000
Total shares of common stock repurchased excluding ASR				17,000,000
Value of common stock repurchased excluding ASR				421,000,000
Remaining authorized amount of common stock under common stock repurchase program				579,000,000
Accumulated other comprehensive loss	119,000,000		108,000,000	119,000,000
Rights plan, beneficial ownership with exclusion	20% or more
Rights plan, grandfathered maximum shares	126,562,500
Rights plan, grandfathered affiliates percentage of shares outstanding	0.10%
Rights plan, beneficial ownership	more than 50%
Rights plan, effect of tender offer	20% or more
Rights plan, shares	0.001 shares
Rights plan, purchase price	100
Rights plan, exercise price	100
Rights plan, qualifying offer	10.00%
Rights plan, redemption price and term	$0.001 per Right, expire November 30, 2015
Treasury Stock [Member]
Stock Repurchase Program [Line Items]
Accelerated share repurchase, value			375,000,000
Additional Paid-in Capital [Member]
Stock Repurchase Program [Line Items]
Accelerated share repurchase, value			125,000,000
Accelerated Share Repurchase Agreement [Member]
Stock Repurchase Program [Line Items]
Stock repurchase program, authorized amount			$ 500,000,000