Income Taxes (Earnings Before Income Taxes) (Details) - USD ($) $ in Millions |
3 Months Ended | 12 Months Ended | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2018 |
Sep. 30, 2018 |
Jun. 30, 2018 |
Mar. 31, 2018 |
Dec. 31, 2017 |
Sep. 30, 2017 |
Jun. 30, 2017 |
Mar. 31, 2017 |
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
Income Tax Disclosure [Abstract] | |||||||||||
Domestic | $ 905.0 | $ 809.4 | $ 739.4 | ||||||||
Foreign | 82.0 | 63.7 | 50.3 | ||||||||
Earnings before income taxes | $ 229.8 | $ 259.4 | $ 265.9 | $ 231.9 | $ 200.8 | $ 226.0 | $ 235.4 | $ 210.9 | $ 987.0 | $ 873.1 | $ 789.7 |