Stock-Based Compensation Narrative (Details) $ / shares in Units, $ in Millions	6 Months Ended		12 Months Ended
	Dec. 31, 2016 $ / shares	Jul. 01, 2016 USD ($)	Dec. 31, 2017 USD ($) $ / shares shares		Dec. 31, 2016 USD ($)		Dec. 31, 2015 USD ($) plan $ / shares		Jul. 02, 2016 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock-based compensation plans | plan							0
Shares authorized | shares									23,000,000
Common Stock, Capital Shares Reserved for Future Issuance | shares			8,000,000
Shares withheld to satisfy tax requirement | shares			243,000
Aggregate value of shares withheld to satisfy tax requirement			$ 15.0
Unrecognized compensation costs, period for recognition			3 years
Granted (in dollars per share) | $ / shares	$ 51.84		$ 58.07				$ 87.96
Exercised (in dollars per share) | $ / shares	26.13		24.77				35.28
Canceled/Forfeited (in dollars per share) | $ / shares	40.57		$ 45.12				$ 58.77
Aggregate intrinsic value of stock options exercised			$ 50.3		$ 77.5		$ 73.4
Cash receipts from stock options exercised		$ 53.3	31.2	[1]	59.9	[1]	51.2	[1]
Tax benefit realized related to stock options exercised			31.7		36.0		33.0
Income tax benefit, stock awards			$ 16.0		15.1		$ 11.8
Stock Compensation Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units granted (in dollars per share) | $ / shares	46.25		$ 57.79				$ 86.14
Units exercised (in dollars per share) | $ / shares	33.01		35.96				51.56
Units canceled/forfeited (in dollars per share) | $ / shares	$ 39.59		$ 43.94				$ 64.58
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			5 years
Expiration period			10 years
Income tax benefit, stock awards			$ 6.4		$ 5.8		$ 4.3
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			5 years
Accounting Standards Update 2016-09 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification			$ 20.3

[1] Cash receipts prior to the Separation were recorded as an increase to Former Parent's Investment. These amounts were $53.3 million in 2016 and $51.2 million in 2015.