Employee Benefit Plans US Pension Assets, Fair Value Inputs (Details) (Pension Benefits, U.S. Plans, USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	$ 1,469.4	$ 1,586.4
Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	550.4	598.3
Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	796.9	884.4
Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	122.1	103.7
United States Government and Government Agencies and Authorities
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	258.1	113.1
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	243.5	105.7
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	14.6	7.4
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
Corporate Debt Securities
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	322.8	270.4
Corporate Debt Securities | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	1.6	97.8
Corporate Debt Securities | Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	321.2	172.6
Corporate Debt Securities | Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0	0
States, Municipalities, and Political Subdivisions
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	2.9	12.9
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
States, Municipalities, and Political Subdivisions | Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	2.9	12.9
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
Opportunistic Credits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	147.8
Opportunistic Credits [Member] | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	62.8
Opportunistic Credits [Member] | Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	85.0
Opportunistic Credits [Member] | Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	0
Private Equity Direct Investments
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	17.2	7.2
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
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
Private Equity Direct Investments | Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	17.2	7.2
Private Equity Funds
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	34.9	29.6
Private Equity Funds | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	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
Private Equity Funds | Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	34.9	29.6
Hedge Funds
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	70.0	66.9
Hedge Funds | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	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
Hedge Funds | Fair Value, Inputs, Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	70.0	66.9
Cash and Cash Equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	52.8	28.4
Cash and Cash Equivalents | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	52.8	28.4
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
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
U.S. Large Cap | Equity Securites
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	181.4	343.9
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
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	181.4	343.9
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
U.S. Mid Cap | Equity Securites
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	88.3	139.6
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
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	88.3	139.6
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
U.S. Small Cap | Equity Securites
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	118.7	231.9
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	118.7	231.9
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
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
International Securities | Equity Securites
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	134.5	266.2
International Securities | Equity Securites | Fair Value, Inputs, Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	71.0	134.5
International Securities | Equity Securites | Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	63.5	131.7
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
Emerging Markets | Equity Securites
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	40.0	76.3
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
Emerging Markets | Equity Securites | Fair Value, Inputs, Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans
Fair Value of Invested Pension Assets	40.0	76.3
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