Pension and Other Post-Retirement Benefit Plans (Pension Plan Assets Measured At Fair Value) (Details) - Pensions - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total pension plan assets, percent		98.00%
U.S.
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		$ 576.4	$ 0.0	$ 0.0
U.S. | Fair value, measurements, recurring
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		576.2	0.0
U.S. | Fair value, measurements, recurring | Cash and cash equivalents
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		41.2	0.0
U.S. | Fair value, measurements, recurring | U.S. companies
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		131.7
U.S. | Fair value, measurements, recurring | International companies
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		33.7
U.S. | Fair value, measurements, recurring | Registered investment companies
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets	[1]	33.6
U.S. | Fair value, measurements, recurring | Common/collective trusts
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets	[1]	31.2
U.S. | Fair value, measurements, recurring | Hedge funds
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets	[1]	194.3
U.S. | Fair value, measurements, recurring | Limited partnerships
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets	[1]	109.7
U.S. | Fair value, measurements, recurring | Real estate and other investments
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		0.8
U.S. | Fair value, measurements, recurring | Level 1
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		207.4	0.0
U.S. | Fair value, measurements, recurring | Level 1 | Cash and cash equivalents
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		41.2	0.0
U.S. | Fair value, measurements, recurring | Level 1 | U.S. companies
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		131.7
U.S. | Fair value, measurements, recurring | Level 1 | International companies
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		33.7
U.S. | Fair value, measurements, recurring | Level 1 | Real estate and other investments
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		0.8
U.S. | Fair value, measurements, recurring | Level 2
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		0.0	0.0
U.S. | Fair value, measurements, recurring | Level 2 | Cash and cash equivalents
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		0.0	0.0
U.S. | Fair value, measurements, recurring | Level 3
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		0.0	0.0
U.S. | Fair value, measurements, recurring | Level 3 | Cash and cash equivalents
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		0.0	0.0
International
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		699.2	229.7	$ 236.0
International | Fair value, measurements, recurring
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		698.4	229.6
International | Fair value, measurements, recurring | Cash and cash equivalents
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		4.8	2.1
International | Fair value, measurements, recurring | U.S. companies
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		106.9
International | Fair value, measurements, recurring | International companies
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		216.7	37.2
International | Fair value, measurements, recurring | Registered investment companies
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets	[1]	72.6	52.7
International | Fair value, measurements, recurring | Common/collective trusts
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets	[1]	13.0	10.6
International | Fair value, measurements, recurring | Insurance contracts
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		208.2	112.2
International | Fair value, measurements, recurring | Hedge funds
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets	[1]	74.7	12.3
International | Fair value, measurements, recurring | Real estate and other investments
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		1.5	2.5
International | Fair value, measurements, recurring | Level 1
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		329.9	41.8
International | Fair value, measurements, recurring | Level 1 | Cash and cash equivalents
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		4.8	2.1
International | Fair value, measurements, recurring | Level 1 | U.S. companies
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		106.9
International | Fair value, measurements, recurring | Level 1 | International companies
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		216.7	37.2
International | Fair value, measurements, recurring | Level 1 | Real estate and other investments
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		1.5	2.5
International | Fair value, measurements, recurring | Level 2
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		208.2	112.2
International | Fair value, measurements, recurring | Level 2 | Cash and cash equivalents
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets			0.0
International | Fair value, measurements, recurring | Level 2 | Insurance contracts
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		208.2	112.2
International | Fair value, measurements, recurring | Level 3
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		0.0	0.0
International | Fair value, measurements, recurring | Level 3 | Cash and cash equivalents
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		$ 0.0	$ 0.0

[1] Certain investments that are measured at fair value using net asset value per share (or its equivalent) have not been classified in the fair value hierarchy.