Equity Incentive Plan (Tables)

12 Months Ended

Dec. 31, 2021

Share-based Payment Arrangement [Abstract]

Table of Performance Share Unit Monte Carlo Assumptions [Table Text Block]

	2021		2020		2019
Risk-free interest rate	0.61	%	0.18	%	1.69	%
Expected life in years	3		3		3
Expected volatility	25	%	26	%	24	%
Expected dividend yield	—		—		—

Schedule of Stock Options, Activity

	Number of Options	Weighted Average Exercise Price		Aggregate Intrinsic Value (in millions)
Outstanding at December 31, 2020	474,103	$	400.21	$	350.6
Granted	28,116	1,390.31
Exercised	(95,549)	214.17
Forfeited	(886)	546.20
Outstanding at December 31, 2021	405,784	512.30		480.8
Options exercisable at December 31, 2021	309,558	$	391.69	$	404.1

Schedule Shares Outstanding under Stock Option Plans, by Exercise Price Range

Number of Options Outstanding	Weighted Average Exercise Price		Remaining Contractual Life of Options Outstanding	Options Exercisable
245,906	$	301.84	3.28	233,228
115,489	$	663.34	6.92	72,155
44,389	$	1,285.26	9.33	4,175
405,784			5.28	309,558

Schedule of Stock Options, Valuation Assumptions

	2021		2020		2019
Risk-free interest rate	0.95	%	0.34	%	1.74	%
Expected life in years	6.3		6.0		6.0
Expected volatility	25	%	26	%	24	%
Expected dividend yield	—		—		—

Schedule Restricted Stock Units, Activity

	Number of Restricted Stock Units	Aggregate Intrinsic Value (in millions)	Number of Performance Share Units	Aggregate Intrinsic Value (in millions)
Outstanding at December 31, 2020	33,096	$37.7	15,341	$17.5
Granted	7,871		2,737
Adjustment for performance results achieved(1)	—		927
Vested	(11,485)		(4,067)
Forfeited	(2,583)		(94)
Outstanding at December 31, 2021	26,899	$45.6	14,844	$25.2