Financing Arrangement (0.75% Convertible Senior Notes Due 2016) (Details)	1 Months Ended	3 Months Ended
	Jul. 31, 2011 days $ / shares	Jun. 30, 2015 USD ($) shares $ / shares	Mar. 31, 2015 USD ($)		Jul. 14, 2011 USD ($) $ / shares
Financing Arrangements
0.75% Convertible senior notes due 2016, net (short-term)		$ 608,000,000	$ 602,000,000	[1]
Temporary Equity		25,000,000	31,000,000	[1]
Debt Instrument, Convertible, Carrying Amount of Equity Component		$ 107,000,000	107,000,000
Debt Instrument, Frequency of Periodic Payment	semiannually
Share Price | $ / shares		$ 67.80
Debt Instrument, Convertible, If-converted Value in Excess of Principal		$ 718,000,000
Debt Instrument, Convertible, Number of Equity Instruments | shares		3,000,000
Convertible Debt
Financing Arrangements
Principal amount		$ 633,000,000	633,000,000
Convertible Senior Notes, Carrying Value		608,000,000	602,000,000
Debt Instrument, Unamortized Discount (Premium), Net		$ 25,000,000	31,000,000
Contractual interest rate of 0.75% Convertible Senior Notes due 2016					0.75%
Debt Instrument, Date of First Required Payment	Jan. 15, 2012
Debt Instrument, Issuance Date	Jul. 15, 2011
Convertible Senior Notes due description	2016
0.75% Convertible Senior Notes due 2016 maturity date	Jul. 15, 2016
Conversion rate of Notes	31.5075
Face amount of Notes					$ 1,000
Debt Instrument, Convertible, Conversion Price | $ / shares					$ 31.74
Number of trading days greater than or equal to the initial conversion price | days	20
Consecutive trading days under conversion trigger | days	30
Trigger price as percent of conversion price	130.00%
Trigger price | $ / shares	$ 41.26
Number of trading day that trading price falls below 98% of last reported sales price multiplied by conversion rate | days	5
Consecutive trading days under conversion trigger, trading price | days	10
Debt trading price as a percentage of stock price times conversion rate	98.00%
Effective interest rate					4.54%
Debt issuance costs					$ 15,000,000
Debt instrument remaining discount amortization period		1 year
Convertible Debt | Liability Component
Financing Arrangements
Convertible Senior Notes, Carrying Value					525,000,000
Debt issuance costs					13,000,000
Convertible Debt | Equity Component
Financing Arrangements
Debt issuance costs					$ 2,000,000
Convertible Debt
Financing Arrangements
Debt Instrument, Fair Value Disclosure		$ 1,342,000,000	$ 1,158,000,000

[1] Derived from audited consolidated financial statements.