Stock Compensation Plans - Option Activity (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding - Number of Shares | shares	3,189,950
Outstanding - beginning of year, Weighted Average Exercise Price | $ / shares	$ 38.21
Granted, Number of Shares | shares	558,760
Granted, Weighted Average-exercise Price | $ / shares	$ 42.61
Exercised, Number of Shares | shares	(803,604)
Exercised, Weighted-average Exercise Price | $ / shares	$ 34.25
Canceled or expired, Number of Shares | shares	(31,834)
Canceled or expired, Weighted-average Exercise Price | $ / shares	$ 42.36
Outstanding - Number of Shares | shares	2,913,272
Outstanding - end of year, Weighted Average Exercise Price | $ / shares	$ 40.10
Outstanding - end of year, Weighted-average Remaining Contractual Term	6 years
Outstanding - end of year, Aggregate Intrinsic Value | $	$ 47.2
Option expected to vest, Number of Shares | shares	2,913,272
Option expected to vest, Weighted-average Exercise Price | $ / shares	$ 40.10
Option expected to vest, Weighted-average Remaining Contractual Term	6 years
Option expected to vest, Aggregate Intrinsic Value | $	$ 47.2
Options exercisable, Number of Shares | shares	1,676,248
Options exercisable, Weighted-average Exercise Price | $ / shares	$ 38.91
Options exercisable, Weighted-average Remaining Contractual Term, Exercisable	5 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value | $	$ 29.2