Employee Benefit Plans (Assets Measured at NAV) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Assets Category:
Fair Value	$ 154.3	$ 291.0
NAV [Member]
Assets Category:
Fair Value	$ 154.1	283.8
Blend [Domain] | NAV [Member]
Assets Category:
Fair Value		7.8
Commingled Pools / Collective Trusts [Member] | U.S. Equity [Member]
Assets Category:
Fair Value		$ 62.7
Redemption Frequency (if currently eligible)	Daily	Daily
Commingled Pools / Collective Trusts [Member] | International Equity [Member]
Assets Category:
Fair Value		$ 39.5
Redemption Frequency (if currently eligible)	Daily	Daily
Commingled Pools / Collective Trusts [Member] | Fixed Income [Member]
Assets Category:
Fair Value	$ 54.6	$ 146.2
Redemption Frequency (if currently eligible)	Daily	Daily
Balanced pension trusts [Member] | International Equity [Member]
Assets Category:
Fair Value		$ 4.0
Redemption Frequency (if currently eligible)	Daily	Daily
Balanced pension trusts [Member] | Fixed Income [Member]
Assets Category:
Fair Value	$ 13.6	$ 12.0
Redemption Frequency (if currently eligible)	Daily	Daily
Pension Funds [Member] | International Equity [Member]
Assets Category:
Fair Value		$ 2.7
Redemption Frequency (if currently eligible)		Daily
Pension Funds [Member] | Fixed Income [Member]
Assets Category:
Fair Value		$ 8.9
Redemption Frequency (if currently eligible)	Daily	Daily
Pension Fund Member | Fixed Income [Member]
Assets Category:
Fair Value	$ 22.0	$ 8.9
Pension Fund Member | Blend [Domain]
Assets Category:
Fair Value		7.8
Fair Value, Inputs, Level 2 [Member]
Assets Category:
Fair Value	154.1	283.8
Fair Value, Inputs, Level 2 [Member] | Blend [Domain]
Assets Category:
Fair Value		7.8
Fair Value, Inputs, Level 2 [Member] | Commingled Pools / Collective Trusts [Member] | Fixed Income [Member]
Assets Category:
Fair Value	54.6	146.2
Fair Value, Inputs, Level 2 [Member] | Balanced pension trusts [Member] | Fixed Income [Member]
Assets Category:
Fair Value	13.6	12.0
Fair Value, Inputs, Level 2 [Member] | Pension Fund Member | Fixed Income [Member]
Assets Category:
Fair Value	$ 22.0	$ 8.9