Employee Benefit Plans - Fair Value of Investment Categories (Details) - USD ($) $ in Millions | 12 Months Ended | |
Dec. 31, 2015 | Dec. 31, 2014 |
U.S. Qualified Plans | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 1,619.9 | $ 0 |
Percentage of Plan Assets | 100.00% | |
U.S. Qualified Plans | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 431.6 | |
U.S. Qualified Plans | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 1,188.3 | |
U.S. Qualified Plans | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
U.S. Qualified Plans | Cash and Cash Equivalents | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 34.3 | |
Percentage of Plan Assets | 2.10% | |
U.S. Qualified Plans | Cash and Cash Equivalents | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 0 | |
U.S. Qualified Plans | Cash and Cash Equivalents | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 34.3 | |
U.S. Qualified Plans | Cash and Cash Equivalents | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
U.S. Qualified Plans | Equity | U.S. large companies | S&P 500 Futures | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 0.7 | |
Percentage of Plan Assets | 0.00% | |
U.S. Qualified Plans | Equity | U.S. large companies | S&P 500 Futures | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 0.7 | |
U.S. Qualified Plans | Equity | U.S. large companies | S&P 500 Futures | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
U.S. Qualified Plans | Equity | U.S. large companies | S&P 500 Futures | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
U.S. Qualified Plans | Equity | U.S. large companies | Growth | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 91.4 | |
Percentage of Plan Assets | 5.60% | |
U.S. Qualified Plans | Equity | U.S. large companies | Growth | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 91.4 | |
U.S. Qualified Plans | Equity | U.S. large companies | Growth | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
U.S. Qualified Plans | Equity | U.S. large companies | Growth | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
U.S. Qualified Plans | Equity | U.S. large companies | Value | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 88.2 | |
Percentage of Plan Assets | 5.40% | |
U.S. Qualified Plans | Equity | U.S. large companies | Value | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 88.2 | |
U.S. Qualified Plans | Equity | U.S. large companies | Value | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
U.S. Qualified Plans | Equity | U.S. large companies | Value | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
U.S. Qualified Plans | Equity | U.S. Small Companies | Value | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 27.1 | |
Percentage of Plan Assets | 1.70% | |
U.S. Qualified Plans | Equity | U.S. Small Companies | Value | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 27.1 | |
U.S. Qualified Plans | Equity | U.S. Small Companies | Value | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
U.S. Qualified Plans | Equity | U.S. Small Companies | Value | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
U.S. Qualified Plans | Equity | International | Growth | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 66.1 | |
Percentage of Plan Assets | 4.10% | |
U.S. Qualified Plans | Equity | International | Growth | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 66.1 | |
U.S. Qualified Plans | Equity | International | Growth | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
U.S. Qualified Plans | Equity | International | Growth | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
U.S. Qualified Plans | Equity | International | Value | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 65.9 | |
Percentage of Plan Assets | 4.10% | |
U.S. Qualified Plans | Equity | International | Value | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 0 | |
U.S. Qualified Plans | Equity | International | Value | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 65.9 | |
U.S. Qualified Plans | Equity | International | Value | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
U.S. Qualified Plans | Global long-term debt instruments | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 1,246.2 | |
Percentage of Plan Assets | 76.90% | |
U.S. Qualified Plans | Global long-term debt instruments | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 158.1 | |
U.S. Qualified Plans | Global long-term debt instruments | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 1,088.1 | |
U.S. Qualified Plans | Global long-term debt instruments | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
UK Plans | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 1,203.8 | $ 0 |
Percentage of Plan Assets | 100.00% | |
UK Plans | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 363.5 | |
UK Plans | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 744.5 | |
UK Plans | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 95.8 | |
UK Plans | Cash and Cash Equivalents | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 32.8 | |
Percentage of Plan Assets | 2.70% | |
UK Plans | Cash and Cash Equivalents | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 32.8 | |
UK Plans | Cash and Cash Equivalents | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
UK Plans | Cash and Cash Equivalents | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
UK Plans | Government | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 260.3 | |
Percentage of Plan Assets | 21.60% | |
UK Plans | Government | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 260.3 | |
UK Plans | Government | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
UK Plans | Government | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
UK Plans | Government and credit - commingled funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 210.8 | |
Percentage of Plan Assets | 17.50% | |
UK Plans | Government and credit - commingled funds | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 0 | |
UK Plans | Government and credit - commingled funds | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 210.8 | |
UK Plans | Government and credit - commingled funds | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
UK Plans | Illiquid credit | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 55.2 | |
Percentage of Plan Assets | 4.60% | |
UK Plans | Illiquid credit | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 0 | |
UK Plans | Illiquid credit | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
UK Plans | Illiquid credit | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 55.2 | |
UK Plans | Equity | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 20.8 | |
Percentage of Plan Assets | 1.70% | |
UK Plans | Equity | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 20.8 | |
UK Plans | Equity | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
UK Plans | Equity | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
UK Plans | Interest rate | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 13.1 | |
Percentage of Plan Assets | 1.10% | |
UK Plans | Interest rate | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 0 | |
UK Plans | Interest rate | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 13.1 | |
UK Plans | Interest rate | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
UK Plans | Currencies | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ (1.6) | |
Percentage of Plan Assets | (0.10%) | |
UK Plans | Currencies | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 0 | |
UK Plans | Currencies | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | (1.6) | |
UK Plans | Currencies | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
UK Plans | Hedge Funds | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 40.6 | |
Percentage of Plan Assets | 3.40% | |
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Notice Period | 60 days | |
UK Plans | Hedge Funds | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 0 | |
UK Plans | Hedge Funds | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
UK Plans | Hedge Funds | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 40.6 | |
UK Plans | Diversified Multi-Asset Funds, Risk Parity | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 235.2 | |
Percentage of Plan Assets | 19.50% | |
UK Plans | Diversified Multi-Asset Funds, Risk Parity | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 0 | |
UK Plans | Diversified Multi-Asset Funds, Risk Parity | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 235.2 | |
UK Plans | Diversified Multi-Asset Funds, Risk Parity | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 0 | |
UK Plans | Diversified Multi-Asset Funds, Dynamic Asset Allocation | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 336.6 | |
Percentage of Plan Assets | 28.00% | |
UK Plans | Diversified Multi-Asset Funds, Dynamic Asset Allocation | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 49.6 | |
UK Plans | Diversified Multi-Asset Funds, Dynamic Asset Allocation | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | 287 | |
UK Plans | Diversified Multi-Asset Funds, Dynamic Asset Allocation | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Defined Benefit Plan, Fair Value of Plan Assets | $ 0 | |