Share-Based Compensation Plans - Stock Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	6 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2016
Number of Options
Beginning options outstanding, number of options	857	783
Granted		344
Exercised	(72)	(122)
Forfeited or expired	(2)	(256)
Ending options outstanding, number of options	783	749
Options exercisable		473
Options expected to vest		266
Weighted-Average Exercise Price Per Share
Beginning options outstanding, weighted average exercise price (in dollars per share)	$ 97.49	$ 99.93
Granted (in dollars per share)		126.67
Exercised (in dollars per share)	69.62	67.68
Forfeited or expired (in dollars per share)	131.91	126.54
Ending options outstanding, weighted average exercise price (in dollars per share)	$ 99.93	108.40
Options exercisable (in dollars per share)		96.89
Options expected to vest (in dollars per share)		$ 128.17
Weighted- Average Remaining Term in Years	6 years 3 months 18 days	6 years 7 months 6 days
Weighted- Average Remaining Term in Years, Options exercisable		5 years 2 months 12 days
Weighted- Average Remaining Term in Years, Options expected to vest		9 years
Aggregate Intrinsic Value	$ 35.6	$ 5.5
Aggregate Intrinsic Value, Options exercisable		5.5
Aggregate Intrinsic Value, Options expected to vest		$ 0.0