Commitments and Contingent Liabilities, Consolidated Lease Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Consolidated Lease Expense [Abstract]
Non-cash lease expense (amortization of ROU assets)	$ 39.0	$ 42.8	$ 0.0
Related accretion expense on lease liability balances	13.0	9.0
Total fixed lease expense	52.0	51.8
Variable lease expense	0.2	6.2
Subtotal operating lease expense	52.2	58.0
Short-term operating leases	49.8	48.6
Total operating lease expense	102.0	106.6	$ 86.4
Cash payments for operating lease liabilities	37.1	48.1
Operating lease income	$ 11.4	$ 14.4