Stock-Based Compensation, Options and Restricted Shares (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended				9 Months Ended		12 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
2000 Employee Option Plan
Stock-Based Compensation
Number of additional stock options that will be granted (in shares)					0
Options exercisable period					10 years
2009 Employee Option Plan
Stock-Based Compensation
Number of additional stock options that will be granted (in shares)					0
Options ratable vesting period					5 years
Options exercisable period					10 years
2017 Employee Option Plan
Stock-Based Compensation
Common Stock reserved for issuance	30,000,000				30,000,000
Shares available for the granting of additional stock options	22,970,400				22,970,400
Options ratable vesting period					5 years
Options exercisable period					10 years
2004 Directors Option Plan
Stock-Based Compensation
Shares available for the granting of additional stock options	140,000				140,000
Number of additional stock options expected to be granted (in shares)	0				0
Options exercisable period					10 years
Stock Options
Stock option activity
Options outstanding at the beginning of the period (in shares)	36,442,270	31,385,806	32,266,391		32,266,391
Options granted (in shares)	143,000	6,886,600
Options exercised (in shares)	(1,757,971)	(1,759,976)	(834,925)
Options forfeited (in shares)	(27,400)	(70,160)	(45,660)
Options outstanding at the end of the period (in shares)	34,799,899	36,442,270	31,385,806		34,799,899		32,266,391
Vested and non-vested options expected to vest at the end of the period (in shares)	32,626,495				32,626,495
Exercisable at the end of the period (in shares)	15,026,939				15,026,939
Weighted Average Exercise Price
Weighted average exercise price, options outstanding at the beginning of the period (in dollars per share)	$ 50.65	$ 44.54	$ 44.14		$ 44.14
Weighted average exercise price, options outstanding at the end of the period (in dollars per share)	51.56	$ 50.65	$ 44.54		51.56		$ 44.14
Weighted average exercise price, vested and non-vested options expected to vest (in dollars per share)	50.85				50.85
Weighted average exercise price, exercisable (in dollars per share)	$ 38.97				$ 38.97
Weighted Average Remaining Contractual Term
Weighted average remaining contractual term of options outstanding	7 years 2 months 12 days	7 years 3 months 29 days	6 years 10 months 6 days				7 years 11 days
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 29 days
Aggregate Intrinsic Value
Aggregate intrinsic value of options outstanding	$ 1,151.2	$ 844.3	$ 835.7		$ 1,151.2		$ 744.1
Aggregate intrinsic value of options, vested and non-vested options expected to vest	1,102.3				1,102.3
Aggregate intrinsic value of options exercisable	$ 686.2				$ 686.2
Status of the Company's non-vested options and changes during the year
Non-vested options at the beginning of the period (in shares)	19,744,700	18,597,170	18,725,570		18,725,570
Options granted (in shares)	143,000	6,886,600
Non-vested options, options vested (in shares)	(87,340)	(5,668,910)	(82,740)
Non-vested options, options forfeited (in shares)	(27,400)	(70,160)	(45,660)
Non-vested options at the end of the period (in shares)	19,772,960	19,744,700	18,597,170		19,772,960		18,725,570
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)	$ 8.28	$ 7.98	$ 7.99		$ 7.99
Weighted average fair value at grant date, options granted (in dollars per share)	9.33	8.77
Weighted average fair value at grant date, options vested (in dollars per share)	8.07	7.91	8.17
Weighted average fair value at grant date, options forfeited (in dollars per share)	7.94	8.20	7.84
Weighted average fair value at the grant date, options outstanding at the end of the period (in dollars per share)	$ 8.29	$ 8.28	$ 7.98		$ 8.29		$ 7.99
Fair Value at Grant Date
Total intrinsic value of stock options exercised	$ 77.0			$ 72.7	$ 191.1	$ 155.3
Total fair value of stock options vested	0.7			$ 0.6	46.2	$ 43.0
Total compensation cost related to non-vested options not yet recognized	$ 132.6				$ 132.6
Weighted average expected amortization period					3 years 5 months 23 days
Restricted Shares | 2012 Directors Restricted Stock Plan
Stock-Based Compensation
Shares available for the granting of additional stock options	124,164				124,164
Restricted share activity
Restricted shares outstanding at the beginning of the period (in shares)	11,526	16,905	16,905		16,905
Restricted shares granted (in shares)	1,379	11,526
Shares vested and issued (in shares)		(16,905)
Restricted shares outstanding at the end of the period (in shares)	12,905	11,526	16,905		12,905		16,905
Fair Value at Grant Date
Fair value at the grant date, restricted shares outstanding at the beginning of the period (in dollars per share)	$ 72.90	$ 57.99	$ 57.99		$ 57.99
Fair value of restricted shares vested and issued (in dollar per share)		57.99
Fair value of restricted shares granted (in dollars per share)	76.13	72.90
Fair value at the grant date, restricted shares outstanding at the end of the period (in dollars per share)	$ 73.25	$ 72.90	$ 57.99		$ 73.25		$ 57.99
Weighted Average Remaining Amortization Term (in years)	7 months 24 days	10 months 21 days	1 month 17 days				4 months 17 days
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