Fair Value Measurements Fair Value of Financial Assets and Liabilities (Details) - USD ($) $ in Millions		Mar. 31, 2020	Dec. 31, 2019
Financial Assets
Derivative Asset, Netting Adjustments	[1]	$ (6.9)	$ 0.0
Assets, Fair Value Disclosure		410.3	24.8
Financial liabilities
Derivative Liability, Netting Adjustments	[1]	(6.9)	0.0
Financial Liabilities Fair Value Disclosure		21.0	46.0
Level 1 [Member]
Financial Assets
Assets, Fair Value Disclosure		20.6	23.1
Financial liabilities
Financial Liabilities Fair Value Disclosure		21.0	26.8
Fair Value, Inputs, Level 2 [Member]
Financial Assets
Assets, Fair Value Disclosure		396.6	1.7
Financial liabilities
Financial Liabilities Fair Value Disclosure		6.9	19.2
Level 3 [Member]
Financial Assets
Assets, Fair Value Disclosure		0.0	0.0
Financial liabilities
Financial Liabilities Fair Value Disclosure		0.0	0.0
Long-term [Member]
Financial Assets
Derivative Asset, Netting Adjustments	[1]	(2.1)	0.0
Investments, Fair Value Disclosure		20.6	23.1
Derivative Asset, Net		19.1	0.2
Financial liabilities
Derivative Liability, Netting Adjustments	[1]	(2.1)	0.0
Fair value of deferred compensation liabilities - long-term		21.0	26.8
Derivative Liability, Net		0.0	0.5
Long-term [Member] | Level 1 [Member]
Financial Assets
Derivative Asset, Fair Value, Gross		0.0	0.0
Financial liabilities
Derivative Liability, Fair Value, Gross		0.0	0.0
Long-term [Member] | Fair Value, Inputs, Level 2 [Member]
Financial Assets
Derivative Asset, Fair Value, Gross		21.2	0.2
Financial liabilities
Derivative Liability, Fair Value, Gross		2.1	0.5
Long-term [Member] | Level 3 [Member]
Financial Assets
Derivative Asset, Fair Value, Gross		0.0	0.0
Financial liabilities
Derivative Liability, Fair Value, Gross		0.0	0.0
Short-term [Member]
Financial Assets
Derivative Asset, Netting Adjustments	[1]	(4.8)	0.0
Derivative Asset, Net		370.6	1.5
Financial liabilities
Derivative Liability, Netting Adjustments	[1]	(4.8)	0.0
Derivative Liability, Net		0.0	18.7
Short-term [Member] | Level 1 [Member]
Financial Assets
Derivative Asset, Fair Value, Gross		0.0	0.0
Financial liabilities
Derivative Liability, Fair Value, Gross		0.0	0.0
Short-term [Member] | Fair Value, Inputs, Level 2 [Member]
Financial Assets
Derivative Asset, Fair Value, Gross		375.4	1.5
Financial liabilities
Derivative Liability, Fair Value, Gross		4.8	18.7
Short-term [Member] | Level 3 [Member]
Financial Assets
Derivative Asset, Fair Value, Gross		0.0	0.0
Financial liabilities
Derivative Liability, Fair Value, Gross		$ 0.0	$ 0.0

[1] The Company nets its derivative contract assets and liabilities outstanding with the same counterparty on the balance sheets for the contracts that contain netting provisions. Refer to Note 7 – Derivative Contracts for additional information regarding the Company's derivative contracts.