Employee Benefit Plans US Pension Assets, Fair Value Inputs (Details) - Pension Benefits, U.S. Plans - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	$ 1,399.6	$ 1,469.4
Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	380.1	550.4
Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	882.9	796.9
Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	136.6	122.1
United States Government and Government Agencies and Authorities
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	244.3	258.1
United States Government and Government Agencies and Authorities | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	231.5	243.5
United States Government and Government Agencies and Authorities | Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	12.8	14.6
United States Government and Government Agencies and Authorities | Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0	0.0
Corporate Debt Securities
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	291.4	322.8
Corporate Debt Securities | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0	1.6
Corporate Debt Securities | Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	291.4	321.2
Corporate Debt Securities | Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0	0.0
States, Municipalities, and Political Subdivisions
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	2.1	2.9
States, Municipalities, and Political Subdivisions | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0	0.0
States, Municipalities, and Political Subdivisions | Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	2.1	2.9
States, Municipalities, and Political Subdivisions | Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0	0.0
Opportunistic Credits
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	163.5	147.8
Opportunistic Credits | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0	62.8
Opportunistic Credits | Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	163.5	85.0
Opportunistic Credits | Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0	0.0
Real Estate
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	83.5
Real Estate | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0
Real Estate | Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	83.5
Real Estate | Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0
Private Equity Direct Investments
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	30.4	17.2
Private Equity Direct Investments | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0	0.0
Private Equity Direct Investments | Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0	0.0
Private Equity Direct Investments | Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	30.4	17.2
Private Equity Funds
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	35.3	34.9
Private Equity Funds | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0	0.0
Private Equity Funds | Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0	0.0
Private Equity Funds | Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	35.3	34.9
Hedge Funds
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	70.9	70.0
Hedge Funds | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0	0.0
Hedge Funds | Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0	0.0
Hedge Funds | Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	70.9	70.0
Cash and Cash Equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	28.0	52.8
Cash and Cash Equivalents | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	28.0	52.8
Cash and Cash Equivalents | Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0	0.0
Cash and Cash Equivalents | Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0	0.0
U.S. Large Cap | Equity Securites
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	176.2	181.4
U.S. Large Cap | Equity Securites | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0	0.0
U.S. Large Cap | Equity Securites | Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	176.2	181.4
U.S. Large Cap | Equity Securites | Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0	0.0
U.S. Mid Cap | Equity Securites
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	55.0	88.3
U.S. Mid Cap | Equity Securites | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0	0.0
U.S. Mid Cap | Equity Securites | Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	55.0	88.3
U.S. Mid Cap | Equity Securites | Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0	0.0
U.S. Small Cap | Equity Securites
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	56.9	118.7
U.S. Small Cap | Equity Securites | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	56.9	118.7
U.S. Small Cap | Equity Securites | Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0	0.0
U.S. Small Cap | Equity Securites | Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0	0.0
International Securities | Equity Securites
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	126.6	134.5
International Securities | Equity Securites | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	63.7	71.0
International Securities | Equity Securites | Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	62.9	63.5
International Securities | Equity Securites | Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0	0.0
Emerging Markets | Equity Securites
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	35.5	40.0
Emerging Markets | Equity Securites | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0.0	0.0
Emerging Markets | Equity Securites | Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	35.5	40.0
Emerging Markets | Equity Securites | Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	$ 0.0	$ 0.0