Stock-Based Compensation, Stock Option Activity (Details) - Stock Options - USD ($) $ / shares in Units, $ in Millions	3 Months Ended			9 Months Ended	12 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2021	Dec. 31, 2020
Stock option activity
Options outstanding at the beginning of the period (in shares)	71,698,138	67,411,970	67,985,648	67,985,648
Non-vested options, options granted (in shares)	95,400	7,215,100	215,080
Options exercised (in shares)	(2,494,842)	(2,882,332)	(757,598)
Options forfeited (in shares)	(200,890)	(46,600)	(31,160)
Options outstanding at the end of the period (in shares)	69,097,806	71,698,138	67,411,970	69,097,806	67,985,648
Vested and non-vested options expected to vest at the end of the period (in shares)	65,684,351			65,684,351
Exercisable at the end of the period (in shares)	37,432,076			37,432,076
Weighted Average Exercise Price
Weighted average exercise price, options outstanding at the beginning of the period (in dollars per share)	$ 41.01	$ 37.77	$ 37.58	$ 37.58
Weighted average exercise price, options granted (in dollars per share)	71.64	66.62	64.69
Weighted average exercise price, options exercised (in dollars per share)	30.30	29.14	28.12
Weighted average exercise price, options forfeited (in dollars per share)	48.28	49.05	42.37
Weighted average exercise price, options outstanding at the end of the period (in dollars per share)	41.42	$ 41.01	$ 37.77	41.42	$ 37.58
Weighted average exercise price, vested and non-vested options expected to vest (in dollars per share)	41.03			41.03
Weighted average exercise price, exercisable (in dollars per share)	$ 34.81			$ 34.81
Weighted Average Remaining Contractual Term
Weighted average remaining contractual term of options outstanding	6 years 7 months 6 days	6 years 9 months 7 days	6 years 6 months 25 days		6 years 9 months 14 days
Weighted average remaining contractual term of options vested options and non-vested expected to vest				6 years 6 months 7 days
Weighted average remaining contractual term of options exercisable				5 years 3 months 29 days
Aggregate Intrinsic Value
Aggregate intrinsic value of options outstanding	$ 2,198.0	$ 1,964.3	$ 1,901.0	$ 2,198.0	$ 1,890.4
Aggregate intrinsic value of options, vested and non-vested options expected to vest	2,114.9			2,114.9
Aggregate intrinsic value of options exercisable	$ 1,438.1			$ 1,438.1