Equity Incentive Plans (Tables)

12 Months Ended

Dec. 31, 2019

Equity Incentive Plans [Abstract]

Assumptions used to determine the fair value of options granted

Option grant assumptions
	2019		2018		2017
Weighted average expected term	5.8 years		5.7 years		6.1 years
Expected volatility	15.6 - 28.9%		15.6 - 30.7%		15.7 - 32.7%
Weighted average volatility	18.4	%	19.8	%	21.0	%
Expected dividends	1.9 - 2.2%		1.5 - 2.2%		1.4 - 1.9%
Weighted average expected dividends	2.2	%	2.0	%	1.9	%
Risk-free rate	1.3 - 2.7%		1.3 - 3.2%		0.5 - 2.5%

Summary of option activity

Summary of option activity
	For the year ended December 31, 2019
	Number (in 000s)		Weighted average exercise price		Aggregate intrinsic value (in 000s)		Weighted average remaining contractual term (years)
Outstanding as of January 1, 2019	11,730		$	65.82
Granted	2,802		92.66
Exercised	(2,622	)	58.70
Forfeited	(235	)	89.20
Expired	(4	)	31.78
Outstanding as of December 31, 2019	11,671		73.40		$	455,691	6.3
Outstanding, net of expected forfeitures	11,547		73.20		453,268		6.3
Outstanding, exercisable (“vested”)	6,744		60.81		348,285		4.8

Changes in restricted stock units

Changes in restricted stock units
	For the year ended December 31, 2019
	Number (in 000s)		Weighted average grant date fair value
Nonvested as of January 1, 2019	957		$	74.58
Granted	271		92.97
Vested	(308	)	62.89
Forfeited	(43	)	84.75
Nonvested as of December 31, 2019	877		83.87

Changes in performance stock units

Changes in performance stock awards
	For the year ended December 31, 2019
	Number (in 000s)		Weighted average grant date fair value
Nonvested as of January 1, 2019	1,248		$	77.35
Granted	415		92.49
Adjustment for performance achievement	267		62.32
Vested	(702	)	62.32
Forfeited	(47	)	87.83
Nonvested as of December 31, 2019	1,181		87.78