Stockholders' Equity (Narrative) (Details) (USD $)	1 Months Ended	3 Months Ended	9 Months Ended	30 Months Ended	1 Months Ended
	Jun. 30, 2012	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2014	Feb. 09, 2015	Sep. 30, 2014
Stockholders' equity
Weighted average grant date fair value			$ 98.29
Compensation cost not yet recognized		$ 9,200,000	$ 9,200,000	$ 9,200,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options		6,800,000	6,800,000	6,800,000
Maximum stock repurchase amount approved by Board of Directors	200,000,000
Number of shares repurchased		157,000		2,922,000
Repurchase of common stock, payments		13,300		134,000,000
Average stock price of shares repurchased (in dollars per share)		$ 84.69		$ 45.87
Remaining stock repurchase amount approved by Board of Directors				66,000,000
Subsequent Event
Stockholders' equity
Maximum stock repurchase amount approved by Board of Directors					200,000
Number of shares repurchased					468,000
Repurchase of common stock, payments					34,000,000
Average stock price of shares repurchased (in dollars per share)					$ 72.55
Remaining stock repurchase amount approved by Board of Directors					32,000,000
Minimum
Stockholders' equity
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options Revenue Targets Range						2,155,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Earnings before Interest, Taxes, Depreciation, and Amortization, Target Range						336,000,000
Maximum
Stockholders' equity
Number of shares granted			160,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options Revenue Targets Range						2,447,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Earnings before Interest, Taxes, Depreciation, and Amortization, Target Range						394,000,000
2006 Equity Incentive Plan (2006 Plan)
Stockholders' equity
Common stock reserved for issuance (in shares)		6,000,000	6,000,000	6,000,000
Maximum number of shares that may be issued through the exercise of incentive stock options		4,500,000	4,500,000	4,500,000
2006 Equity Incentive Plan (2006 Plan) | Nonvested stock units issued (NSUs)
Stockholders' equity
Number of shares granted			143,000
Weighted average grant date fair value			$ 83.99
NSUs granted that will vest at the end of each of the three years after the performance goals are achieved (as a percent)			33.33%
Award vesting period of the grants			3 years
2006 Equity Incentive Plan (2006 Plan) | Time-based equity award
Stockholders' equity
Number of shares granted		10,000	33,000
Weighted average grant date fair value		$ 89.43	$ 82.64
2006 Equity Incentive Plan (2006 Plan) | Time-based equity award | Subsequent Event
Stockholders' equity
Number of shares granted					13,000
Weighted average grant date fair value					$ 68.96
Compensation cost not yet recognized					$ 900,000