Stock-Based Compensation (Details) $ / shares in Units, $ in Millions	3 Months Ended				9 Months Ended		12 Months Ended
	Sep. 30, 2016 USD ($) item $ / shares shares	Jun. 30, 2016 USD ($) $ / shares shares	Mar. 31, 2016 USD ($) $ / shares shares	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) item $ / shares shares	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($) $ / shares shares
2000 Employee Option Plan
Stock-Based Compensation
Number of additional stock options that can be granted | item	0				0
Options exercisable period					10 years
2009 Employee Option Plan
Stock-Based Compensation
Common Stock reserved for issuance	58,000,000				58,000,000
Shares available for the granting of additional stock options	12,026,450				12,026,450
Options exercisable period					10 years
Options ratable vesting period					5 years
2004 Directors Option Plan
Stock-Based Compensation
Shares available for the granting of additional stock options	140,000				140,000
Options exercisable period					10 years
Number of additional stock options expected to be granted (in shares)	0				0
Stock Options
Stock option activity
Options outstanding at the beginning of the period (in shares)	35,479,573	30,681,955	31,136,475		31,136,475
Options granted (in shares)	130,000	7,138,450	245,000
Options exercised (in shares)	(2,077,253)	(1,951,432)	(650,840)
Options forfeited (in shares)	(190,540)	(389,400)	(48,680)
Options outstanding at the end of the period (in shares)	33,341,780	35,479,573	30,681,955		33,341,780		31,136,475
Vested and non-vested options expected to vest at the end of the period (in shares)	31,422,851				31,422,851
Exercisable at the end of the period (in shares)	14,558,550				14,558,550
Weighted Average Exercise Price
Weighted average exercise price, options outstanding at the beginning of the period (in dollars per share) | $ / shares	$ 42.52	$ 37.97	$ 37.62		$ 37.62
Weighted average exercise price, options outstanding at the end of the period (in dollars per share) | $ / shares	43.56	$ 42.52	$ 37.97		43.56		$ 37.62
Weighted average exercise price, vested and non-vested options expected to vest (in dollars per share) | $ / shares	43.09				43.09
Weighted average exercise price, exercisable (in dollars per share) | $ / shares	$ 32.39				$ 32.39
Weighted Average Remaining Contractual Term
Weighted average remaining contractual term of options outstanding	7 years 2 months 9 days	7 years 3 months 7 days	6 years 9 months				6 years 11 months 1 day
Weighted average remaining contractual term of options vested options and non-vested expected to vest	7 years 1 month 10 days
Weighted average remaining contractual term of options exercisable	5 years 6 months 7 days
Aggregate Intrinsic Value
Aggregate intrinsic value of options outstanding | $	$ 712.0	$ 534.2	$ 609.9		$ 712.0		$ 491.0
Aggregate intrinsic value of options, vested and non-vested options expected to vest | $	685.9				685.9
Aggregate intrinsic value of options exercisable | $	$ 473.7				$ 473.7
Status of the Company's non-vested options and changes during the year
Non-vested options at the beginning of the period (in shares)	18,910,510	17,474,960	17,323,040		17,323,040
Options granted (in shares)	130,000	7,138,450	245,000
Non-vested options, options vested (in shares)	(66,740)	(5,313,500)	(44,400)
Non-vested options, options forfeited (in shares)	(190,540)	(389,400)	(48,680)
Non-vested options at the end of the period (in shares)	18,783,230	18,910,510	17,474,960		18,783,230		17,323,040
Weighted Average Fair Value at Grant Date
Weighted average fair value at the grant date, options outstanding at the beginning of the period (in dollars per share) | $ / shares	$ 7.99	$ 8.22	$ 8.24		$ 8.24
Weighted average fair value at grant date, options granted (in dollars per share) | $ / shares	7.34	7.40	6.98
Weighted average fair value at grant date, options vested (in dollars per share) | $ / shares	8.28	7.91	9.82
Weighted average fair value at grant date, options forfeited (in dollars per share) | $ / shares	8.23	8.33	8.38
Weighted average fair value at the grant date, options outstanding at the end of the period (in dollars per share) | $ / shares	$ 7.99	$ 7.99	$ 8.22		$ 7.99		$ 8.24
Fair Value at Grant Date
Total intrinsic value of stock options exercised | $	$ 72.7			$ 3.9	$ 155.3	$ 61.8
Total fair value of stock options vested | $	0.6			$ 0.4	43.0	$ 39.8
Total compensation cost related to non-vested options not yet recognized | $	123.7				$ 123.7
Weighted average expected amortization period					3 years 5 months 23 days
Restricted Shares
Fair Value at Grant Date
Total compensation cost related to non-vested restricted shares not yet recognized | $	$ 0.6				$ 0.6
Weighted average expected amortization period					7 months 24 days
Restricted Shares | 2012 Directors Restricted Stock Plan
Stock-Based Compensation
Shares available for the granting of additional stock options	137,069				137,069
Restricted share activity
Restricted shares outstanding at the beginning of the period (in shares)	16,905	17,256	17,256		17,256
Shares vested and issued (in shares)		(17,256)
Restricted shares granted (in shares)		16,905
Restricted shares outstanding at the end of the period (in shares)	16,905	16,905	17,256		16,905		17,256
Fair Value at Grant Date
Fair value at the grant date, restricted shares outstanding at the beginning of the period (in dollars per share) | $ / shares	$ 57.99	$ 57.97	$ 57.97		$ 57.97
Fair value of restricted shares vested and issued (in dollar per share) | $ / shares		57.97
Fair value of restricted shares granted (in dollars per share) | $ / shares		57.99
Fair value at the grant date, restricted shares outstanding at the end of the period (in dollars per share) | $ / shares	$ 57.99	$ 57.99	$ 57.97		$ 57.99		$ 57.97
Weighted Average Remaining Amortization Term (in years)	7 months 24 days	10 months 24 days	1 month 24 days				4 months 21 days