Consolidated Statements of Income and Comprehensive Income (Parenthetical) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Mar. 31, 2017 |
Mar. 31, 2016 |
Jun. 30, 2017 |
Jun. 30, 2016 |
|
| Income Statement [Abstract] | ||||
| Reclassification adjustments to cash flow hedges included in net income, tax | $ 0.6 | $ 0.6 | $ 1.2 | $ 1.1 |
| Amortization of pension and postretirement plans actuarial loss and prior service cost, tax | 1.2 | 1.0 | 2.3 | 2.0 |
| Changes in unfunded employee benefit obligations, tax | $ 0.0 | $ 2.0 | $ 0.0 | $ 2.0 |