Pension and Other Post-Retirement Benefit Plans (Pension Plan Assets Measured At Fair Value) (Details) - Pensions - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total pension plan assets, percent		86.00%
International
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		$ 746.2	$ 657.8	$ 570.6
International | Fair value, measurements, recurring
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		746.2	659.7
International | Fair value, measurements, recurring | Cash and cash equivalents
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		66.3	10.0
International | Fair value, measurements, recurring | U.S. companies
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		96.3	70.4
International | Fair value, measurements, recurring | International companies
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		209.1	251.5
International | Fair value, measurements, recurring | Registered investment companies
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets	[1]	68.2	63.4
International | Fair value, measurements, recurring | Insurance contracts
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		154.0	138.5
International | Fair value, measurements, recurring | Hedge funds
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets	[1]	98.3	82.0
International | Fair value, measurements, recurring | Limited partnerships
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets	[1]	14.5	7.9
International | Fair value, measurements, recurring | Real estate and other investments
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		39.5	36.0
International | Fair value, measurements, recurring | Level 1
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		411.2	367.9
International | Fair value, measurements, recurring | Level 1 | Cash and cash equivalents
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		66.3	10.0
International | Fair value, measurements, recurring | Level 1 | U.S. companies
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		96.3	70.4
International | Fair value, measurements, recurring | Level 1 | International companies
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		209.1	251.5
International | Fair value, measurements, recurring | Level 1 | Real estate and other investments
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		39.5	36.0
International | Fair value, measurements, recurring | Level 2
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		154.0	138.5
International | Fair value, measurements, recurring | Level 2 | Insurance contracts
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		154.0	138.5
International | Fair value, measurements, recurring | Level 3
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets			0.0
International | Fair value, measurements, recurring | Fair Value Measured at Net Asset Value Per Share
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		181.0	153.3
International | Fair value, measurements, recurring | Fair Value Measured at Net Asset Value Per Share | Registered investment companies
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		68.2	63.4
International | Fair value, measurements, recurring | Fair Value Measured at Net Asset Value Per Share | Hedge funds
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		98.3	82.0
International | Fair value, measurements, recurring | Fair Value Measured at Net Asset Value Per Share | Limited partnerships
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		14.5	7.9
UNITED STATES
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		483.7	520.0
UNITED STATES | Fair value, measurements, recurring
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		483.7	520.0
UNITED STATES | Fair value, measurements, recurring | Cash and cash equivalents
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		38.1	50.5
UNITED STATES | Fair value, measurements, recurring | U.S. companies
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		83.3	110.3
UNITED STATES | Fair value, measurements, recurring | International companies
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		1.1	5.4
UNITED STATES | Fair value, measurements, recurring | Registered investment companies
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets	[1]	38.4	36.3
UNITED STATES | Fair value, measurements, recurring | Common/collective trusts
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets	[1]		12.5
UNITED STATES | Fair value, measurements, recurring | Hedge funds
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets	[1]	160.9	164.3
UNITED STATES | Fair value, measurements, recurring | Limited partnerships
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets	[1]	160.9	139.4
UNITED STATES | Fair value, measurements, recurring | Real estate and other investments
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		1.0	1.3
UNITED STATES | Fair value, measurements, recurring | Level 1
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		123.5	167.5
UNITED STATES | Fair value, measurements, recurring | Level 1 | Cash and cash equivalents
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		38.1	50.5
UNITED STATES | Fair value, measurements, recurring | Level 1 | U.S. companies
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		83.3	110.3
UNITED STATES | Fair value, measurements, recurring | Level 1 | International companies
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		1.1	5.4
UNITED STATES | Fair value, measurements, recurring | Level 1 | Real estate and other investments
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		1.0	1.3
UNITED STATES | Fair value, measurements, recurring | Level 2
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets			0.0
UNITED STATES | Fair value, measurements, recurring | Level 3
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets			0.0
UNITED STATES | Fair value, measurements, recurring | Fair Value Measured at Net Asset Value Per Share
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		360.2	352.5
UNITED STATES | Fair value, measurements, recurring | Fair Value Measured at Net Asset Value Per Share | Registered investment companies
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		38.4	36.3
UNITED STATES | Fair value, measurements, recurring | Fair Value Measured at Net Asset Value Per Share | Common/collective trusts
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets			12.5
UNITED STATES | Fair value, measurements, recurring | Fair Value Measured at Net Asset Value Per Share | Hedge funds
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		160.9	164.3
UNITED STATES | Fair value, measurements, recurring | Fair Value Measured at Net Asset Value Per Share | Limited partnerships
Pension and Other Postretirement Benefit Plans Disclosure [Line Items]
Total plan assets		$ 160.9	$ 139.4

[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.