Stock Compensation Plans - Option Activity (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding - Number of Shares | shares	3,279,868
Outstanding - beginning of year, Weighted Average Exercise Price | $ / shares	$ 35.60
Granted, Number of Shares | shares	733,580
Granted, Weighted Average-exercise Price | $ / shares	$ 27.75
Exercised, Number of Shares | shares	152,720
Exercised, Weighted-average Exercise Price | $ / shares	$ 26.89
Canceled or expired, Number of Shares | shares	(77,231)
Canceled or expired, Weighted-average Exercise Price | $ / shares	$ 36.55
Outstanding - Number of Shares | shares	3,783,497
Outstanding - end of year, Weighted Average Exercise Price | $ / shares	$ 34.41
Outstanding - end of year, Weighted-average Remaining Contractual Term	6 years
Outstanding - end of year, Aggregate Intrinsic Value | $	$ 22.2
Option expected to vest, Number of Shares | shares	3,751,006
Option expected to vest, Weighted-average Exercise Price | $ / shares	$ 34.41
Option expected to vest, Weighted-average Remaining Contractual Term	6 years
Option expected to vest, Aggregate Intrinsic Value | $	$ 22.0
Options exercisable, Number of Shares | shares	2,370,847
Options exercisable, Weighted-average Exercise Price | $ / shares	$ 34.38
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 | $	$ 13.6