Employee Benefit Plans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	May. 19, 2015
Share-Based Compensation Plans
Common shares outstanding from equtiy awards through acquisition	1,700,000
Common stock - shares issued	384,000,000	416,200,000
Stock Option Activities
Beginning Balance, Number of Shares	9,900,000	23,100,000	34,100,000
Options Canceled, Number of Shares	(100,000)	(600,000)	(1,300,000)
Options Exercised, Number of Shares	(3,500,000)	(5,400,000)	(5,600,000)
Options Expired, Number of Shares	(2,700,000)	(7,200,000)	(4,100,000)
Ending Balance, Number of Shares	3,600,000	9,900,000	23,100,000	34,100,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Beginning Balance, Weighted Average Exercise Price (in USD per share)	$ 24.87	$ 25.15	$ 24.13
Options Canceled, Weighted Average Exercise Price (in USD per share)	23.65	30.15	29.56
Options Exercised, Weighted Average Exercise Price (in USD per share)	19.78	19.76	15.58
Options Expired, Weighted Average Exercise Price (in USD per share)	27.99	29.11	28.35
Ending Balance, Weighted Average Exercise Price (in USD per share)	$ 27.52	$ 24.87	$ 25.15	$ 24.13
Weighted Average Remaining Contractual Term at Period End	2 years 1 month 6 days	2 years	2 years 4 months 24 days	3 years 1 month 6 days
Aggregate Intrinsic Value at Period End	$ 16,600,000	$ 24,700,000	$ 44,600,000	$ 52,500,000
Vested or Expected-to-Vest Options, Number of Shares at Period End	3,600,000
Vested or Expected-to-Vest Options, Weighted Average Exercise Price at Period End (in USD per share)	$ 27.58
Vested and Expected-to-Vest Options, Weighted Average Remaining Contractual Term at Period End	2 years 1 month 6 days
Vested or Expected-to-Vest Options, Aggregate Intrinsic Value at Period End	$ 16,300,000
Exercisable Options, Number of Shares at Period End	3,400,000
Exercisable Options, Weighted Average Exercise Price at Period End (in USD per share)	$ 28.82
Exercisable Options, Weighted Average Remaining Contractual Term at Period End	1 year 9 months 18 days
Exercisable Options, Aggregate Intrinsic Value at Period End	$ 12,100,000
Share Price (in USD per share)	$ 27.60
Intrinsic value of options exercised in period	$ 27,500,000	33,400,000	29,400,000
Total Fair Value of Options Vested	$ 7,000,000	$ 20,800,000	$ 45,200,000
Mykonos, Contrail and WANDL [Member]
Share-Based Compensation Plans
Options Assumed, Number of Shares		1,500,000
Stock Compensation Plan [Member]
Share-Based Compensation Plans
Number of shares of common stock reserved for future issuance for equity incentive plans	66,500,000
Stock Options [Member] | Prior to 2006 [Member] | Prior to 2006 [Member]
Share-Based Compensation Plans
Maximum Term for Options	10 years
Equity Incentive Plan 2015 [Member]
Share-Based Compensation Plans
Number of shares in authorized	38,000,000.0				38,000,000
Number of Shares Available for Future Issuance	36,700,000
Equity Incentive Plan 2015, 2006, and 1996 [Member]
Share-Based Compensation Plans
Shares outstanding under 2006 plan	20,500,000
Equity Incentive Plan 1996 and 2006 [Member]
Share-Based Compensation Plans
Maximum Additional Shares Expire Unexercised, Under 1996 and 2000 Plan	29,000,000.0				29,000,000
Number of Shares Available for Future Issuance	0
Equity Incentive Plan 2006 [Member]
Share-Based Compensation Plans
Number of Shares Available for Future Issuance		47,800,000
Stock Option Activities
Options Canceled, Number of Shares	(100,000)
Options Expired, Number of Shares	(2,700,000)
Equity Incentive Plan 2006 [Member] | Stock Options [Member] | From 2006 [Member]
Share-Based Compensation Plans
Maximum Term for Options	7 years
Employee Stock Purchase Plan 2008 [Member]
Share-Based Compensation Plans
Number of Shares Available for Future Issuance	7,600,000
Maximum Term for Options	1 year
Discount on share purchase price for purchases made under ESPP	15.00%
Periodic Payroll Deduction - Percentage of Base Salary	10.00%
Maximum Purchase of Common Stock, Shares	6,000
Number of shares of common stock reserved for future issuance for equity incentive plans	26,000,000
Period for share purchases under ESPP	12 months
Maximum Purchase of Common Stock, Value	$ 25,000
Common stock - shares issued	18,400,000
Employee Stock Purchase Plan 2008 Additional Authorization [Member]
Share-Based Compensation Plans
Number of shares of common stock reserved for future issuance for equity incentive plans	7,000,000