Stockholders' Equity 2 (Details) (USD $)	1 Months Ended	12 Months Ended							1 Months Ended	12 Months Ended		1 Months Ended	3 Months Ended
	Jan. 31, 2012	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013 Treasury Stock	Mar. 31, 2012 Treasury Stock	Mar. 31, 2013 Additional Paid-in Capital	Mar. 31, 2012 Additional Paid-in Capital	Jan. 31, 2012 Stock Repurchase Program [Member]	Mar. 31, 2014 Stock Repurchase Program [Member]	Mar. 31, 2013 Stock Repurchase Program [Member]	Jan. 31, 2012 Accelerated Share Repurchase Agreement [Member]	Jun. 30, 2012 Accelerated Share Repurchase Agreement [Member]	Mar. 31, 2012 Accelerated Share Repurchase Agreement [Member]	Mar. 31, 2012 Accelerated Share Repurchase Agreement [Member] Treasury Stock	Mar. 31, 2012 Accelerated Share Repurchase Agreement [Member] Additional Paid-in Capital
Equity [Abstract]
Capital allocation program, Authorized amount	$ 2,500,000,000
Accumulated other comprehensive loss		171,000,000	155,000,000	108,000,000
Amount of loss reclassified into interest expense, net relating to sale of marketable securities				less than $1 million
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 (in dollars per share)		100
Rights plan, Exercise price (in dollars per share)		100
Rights plan, Qualifying offer percentage		10.00%
Rights plan, Redemption price and term		$0.001 per Right, and the Rights Agreement expire November 30, 2015
Stock Repurchase Program [Line Items]
Stock repurchase program, Authorized amount									1,500,000,000			500,000,000
Accelerated share repurchase, Amount paid to bank												500,000,000
Number of initial shares received under accelerated share repurchase agreement														15,000,000
Accelerated share repurchase, Value			0	500,000,000	125,000,000	375,000,000	(125,000,000)	125,000,000							375,000,000	125,000,000
Number of additional shares received under accelerated share repurchase agreement													3,700,000
Total shares of common stock repurchased, excluding ASR										16,000,000	20,000,000
Value of common stock repurchased, excluding ASR										$ 505,000,000	$ 495,000,000