Employee Benefit Plans US Pension Assets, Fair Value Measurement by Input Level (Details) - Domestic Plan - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	$ 1,456.8	$ 1,575.0
Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	315.5	325.7
Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	316.9	353.7
Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	824.4	895.6
U.S. Large Cap
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	83.0	103.3
U.S. Large Cap | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
U.S. Large Cap | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
U.S. Large Cap | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
U.S. Large Cap | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	83.0	103.3
U.S. Small Cap
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	18.9	45.2
U.S. Small Cap | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	18.9	45.2
U.S. Small Cap | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
U.S. Small Cap | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
U.S. Small Cap | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Global
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	290.3	325.9
Global | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Global | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Global | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Global | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	290.3	325.9
International
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	24.6	35.7
International | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
International | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
International | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
International | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	24.6	35.7
Emerging Markets
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	44.1	61.5
Emerging Markets | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Emerging Markets | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Emerging Markets | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Emerging Markets | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	44.1	61.5
U.S. Government and Agencies
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	257.4	260.4
U.S. Government and Agencies | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	257.4	248.5
U.S. Government and Agencies | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	11.9
U.S. Government and Agencies | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
U.S. Government and Agencies | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Corporate
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	311.2	335.5
Corporate | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Corporate | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	311.2	335.5
Corporate | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Corporate | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
State and Municipal Securities
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	5.7	6.3
State and Municipal Securities | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
State and Municipal Securities | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	5.7	6.3
State and Municipal Securities | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
State and Municipal Securities | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Opportunistic Credits
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	192.0	193.3
Opportunistic Credits | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Opportunistic Credits | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Opportunistic Credits | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Opportunistic Credits | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	192.0	193.3
Real Estate
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	102.8	96.1
Real Estate | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Real Estate | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Real Estate | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Real Estate | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	102.8	96.1
Private Equity Direct Investments
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	53.5	45.1
Private Equity Direct Investments | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Private Equity Direct Investments | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Private Equity Direct Investments | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Private Equity Direct Investments | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	53.5	45.1
Private Equity Funds of Funds
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	34.0	34.5
Private Equity Funds of Funds | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Private Equity Funds of Funds | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Private Equity Funds of Funds | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Private Equity Funds of Funds | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	34.0	34.5
Hedge Funds of Funds
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.1	0.2
Hedge Funds of Funds | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Hedge Funds of Funds | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Hedge Funds of Funds | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Hedge Funds of Funds | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.1	0.2
Cash Equivalents
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	39.2	32.0
Cash Equivalents | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	39.2	32.0
Cash Equivalents | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Cash Equivalents | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	0.0	0.0
Cash Equivalents | Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure
Fair Value of Plan Assets	$ 0.0	$ 0.0