Benefit Plans Benefit Plans - Allocation of Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Emerging markets [Member] | Pension Benefits | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 19.5
Emerging markets [Member] | Pension Benefits | Equity securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0
Emerging markets [Member] | Pension Benefits | Equity securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0.0
Special Situation Private Equity and Debt Funds [Member] | Private equity funds
Defined Benefit Plan Disclosure [Line Items]
Actual	25.00%	26.00%
Venture Private Equity Funds [Member] | Private equity funds
Defined Benefit Plan Disclosure [Line Items]
Actual	33.00%	31.00%
Buyout Private Equity Funds [Member] | Private equity funds
Defined Benefit Plan Disclosure [Line Items]
Actual	42.00%	43.00%
U.S. Plans | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	4.24%	4.62%
Acquired benefit plans and other	$ 0.0	$ 0.0
Actual	0.00%
Actual		0.00%
Fair value of plan assets	$ 378.7	$ 351.7	$ 347.9
U.S. Plans | Pension Benefits | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	93.8	85.4
U.S. Plans | Pension Benefits | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	237.7	218.9
U.S. Plans | Pension Benefits | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	47.2	47.4
U.S. Plans | Pension Benefits | Cash and short-term investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3.5	3.4
U.S. Plans | Pension Benefits | Cash and short-term investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3.5	3.4
U.S. Plans | Pension Benefits | Cash and short-term investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | Pension Benefits | Cash and short-term investments | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | Pension Benefits | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	32.0	28.2
U.S. Plans | Pension Benefits | Mutual funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	32.0	28.2
U.S. Plans | Pension Benefits | Mutual funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | Pension Benefits | Mutual funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | Pension Benefits | U.S. corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	50.0	44.8
U.S. Plans | Pension Benefits | U.S. corporate bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | Pension Benefits | U.S. corporate bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	50.0	44.8
U.S. Plans | Pension Benefits | U.S. corporate bonds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | Pension Benefits | International corporate bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | Pension Benefits | International corporate bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | Pension Benefits | International corporate bonds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | Pension Benefits | U.S. government
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	7.7	7.7
U.S. Plans | Pension Benefits | U.S. government | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | Pension Benefits | U.S. government | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	7.7	7.7
U.S. Plans | Pension Benefits | U.S. government | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | Pension Benefits | Fixed and index funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.6	1.5
U.S. Plans | Pension Benefits | Fixed and index funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | Pension Benefits | Fixed and index funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.6	1.5
U.S. Plans | Pension Benefits | Fixed and index funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | Pension Benefits | Real estate
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	19.2	18.1
U.S. Plans | Pension Benefits | Real estate | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | Pension Benefits | Real estate | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | Pension Benefits | Real estate | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	19.2	18.1
U.S. Plans | Pension Benefits | Other common collective trusts
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	159.9	148.4
U.S. Plans | Pension Benefits | Other common collective trusts | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | Pension Benefits | Other common collective trusts | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	159.9	148.4
U.S. Plans | Pension Benefits | Other common collective trusts | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | Pension Benefits | Multi-strategy hedge funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	18.9	17.6
U.S. Plans | Pension Benefits | Multi-strategy hedge funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | Pension Benefits | Multi-strategy hedge funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | Pension Benefits | Multi-strategy hedge funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	18.9	17.6
U.S. Plans | Pension Benefits | Private equity funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	9.1	11.7
U.S. Plans | Pension Benefits | Private equity funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | Pension Benefits | Private equity funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | Pension Benefits | Private equity funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	9.1	11.7
U.S. Plans | Pension Benefits | Other Alternative Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | Pension Benefits | Other Alternative Investments [Member] | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | Pension Benefits | Other Alternative Investments [Member] | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | Pension Benefits | Other Alternative Investments [Member] | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0.0	$ 0.0
U.S. Plans | Equity securities | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Actual	0.00%
Actual	0.00%	0.00%
U.S. Plans | Debt securities | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Actual	0.00%
Actual	0.00%	0.00%
U.S. Plans | Real estate | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Actual	0.00%
Actual	0.00%	0.00%
U.S. Plans | Other | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Actual	0.00%
Actual	0.00%	0.00%
U.S. Plans | Emerging markets [Member] | Pension Benefits | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		$ 16.5
U.S. Plans | Emerging markets [Member] | Pension Benefits | Equity securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0.0
U.S. Plans | Emerging markets [Member] | Pension Benefits | Equity securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 19.5	16.5
U.S. Plans | Emerging markets [Member] | Pension Benefits | Equity securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0.0
U.S. Plans | U.S. small cap core | Pension Benefits | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	19.0	16.9
U.S. Plans | U.S. small cap core | Pension Benefits | Equity securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	19.0	16.9
U.S. Plans | U.S. small cap core | Pension Benefits | Equity securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | U.S. small cap core | Pension Benefits | Equity securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | U.S. mid cap value | Pension Benefits | Equity securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | U.S. mid cap value | Pension Benefits | Equity securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | U.S. mid cap value | Pension Benefits | Equity securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | International developed markets | Pension Benefits | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	39.3	36.9
U.S. Plans | International developed markets | Pension Benefits | Equity securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	39.3	36.9
U.S. Plans | International developed markets | Pension Benefits | Equity securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
U.S. Plans | International developed markets | Pension Benefits | Equity securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0.0	$ 0.0
Foreign Plan [Member] | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	1.47%	1.16%
Acquired benefit plans and other	$ 23.0	$ 625.1
Actual	0.00%
Actual	0.00%	0.00%
Fair value of plan assets	$ 359.5	$ 482.9	$ 0.0
Foreign Plan [Member] | Pension Benefits | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	184.8	163.2
Foreign Plan [Member] | Pension Benefits | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	92.9	89.1
Foreign Plan [Member] | Pension Benefits | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	81.8	230.6
Foreign Plan [Member] | Pension Benefits | Cash and short-term investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	82.5	92.3
Foreign Plan [Member] | Pension Benefits | Cash and short-term investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	82.1	92.3
Foreign Plan [Member] | Pension Benefits | Cash and short-term investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.4	0.0
Foreign Plan [Member] | Pension Benefits | Cash and short-term investments | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | Pension Benefits | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	77.5	61.6
Foreign Plan [Member] | Pension Benefits | Mutual funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	77.5	61.6
Foreign Plan [Member] | Pension Benefits | Mutual funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | Pension Benefits | Mutual funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | Pension Benefits | U.S. corporate bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | Pension Benefits | U.S. corporate bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | Pension Benefits | U.S. corporate bonds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | Pension Benefits | International corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	86.9	77.3
Foreign Plan [Member] | Pension Benefits | International corporate bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5.9	0.0
Foreign Plan [Member] | Pension Benefits | International corporate bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	81.0	77.3
Foreign Plan [Member] | Pension Benefits | International corporate bonds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | Pension Benefits | U.S. government | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | Pension Benefits | U.S. government | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | Pension Benefits | U.S. government | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | Pension Benefits | Fixed and index funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	11.7	5.4
Foreign Plan [Member] | Pension Benefits | Fixed and index funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	7.4	0.0
Foreign Plan [Member] | Pension Benefits | Fixed and index funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4.3	5.4
Foreign Plan [Member] | Pension Benefits | Fixed and index funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | Pension Benefits | Real estate
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4.7	4.3
Foreign Plan [Member] | Pension Benefits | Real estate | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | Pension Benefits | Real estate | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4.7	4.3
Foreign Plan [Member] | Pension Benefits | Real estate | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | Pension Benefits | Other common collective trusts | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | Pension Benefits | Other common collective trusts | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | Pension Benefits | Other common collective trusts | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | Pension Benefits | Multi-strategy hedge funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.6	2.8
Foreign Plan [Member] | Pension Benefits | Multi-strategy hedge funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | Pension Benefits | Multi-strategy hedge funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1.6	2.1
Foreign Plan [Member] | Pension Benefits | Multi-strategy hedge funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.7
Foreign Plan [Member] | Pension Benefits | Private equity funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | Pension Benefits | Private equity funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | Pension Benefits | Private equity funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | Pension Benefits | Other Alternative Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	82.7	229.9
Foreign Plan [Member] | Pension Benefits | Other Alternative Investments [Member] | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | Pension Benefits | Other Alternative Investments [Member] | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.9	0.0
Foreign Plan [Member] | Pension Benefits | Other Alternative Investments [Member] | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 81.8	$ 229.9
Foreign Plan [Member] | Equity securities | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Actual	0.00%
Actual	0.00%	0.00%
Foreign Plan [Member] | Debt securities | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Actual	0.00%
Actual	0.00%	0.00%
Foreign Plan [Member] | Real estate | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Actual	0.00%
Actual	0.00%	0.00%
Foreign Plan [Member] | Other | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Actual	0.00%
Actual	0.00%	0.00%
Foreign Plan [Member] | Emerging markets [Member] | Pension Benefits | Equity securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		$ 0.0
Foreign Plan [Member] | Emerging markets [Member] | Pension Benefits | Equity securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0.0	0.0
Foreign Plan [Member] | Emerging markets [Member] | Pension Benefits | Equity securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0.0
Foreign Plan [Member] | U.S. small cap core | Pension Benefits | Equity securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | U.S. small cap core | Pension Benefits | Equity securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | U.S. small cap core | Pension Benefits | Equity securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | U.S. mid cap value | Pension Benefits | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.7	0.1
Foreign Plan [Member] | U.S. mid cap value | Pension Benefits | Equity securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.7	0.1
Foreign Plan [Member] | U.S. mid cap value | Pension Benefits | Equity securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | U.S. mid cap value | Pension Benefits | Equity securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | International developed markets | Pension Benefits | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	11.2	9.2
Foreign Plan [Member] | International developed markets | Pension Benefits | Equity securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	11.2	9.2
Foreign Plan [Member] | International developed markets | Pension Benefits | Equity securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.0	0.0
Foreign Plan [Member] | International developed markets | Pension Benefits | Equity securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0.0	$ 0.0