Contingencies and Commitments (Narrative) (Details) $ in Millions		12 Months Ended
	Jan. 19, 2022 USD ($)	Dec. 31, 2021 USD ($) contract	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Loss Contingencies [Line Items]
Loss contingency, estimate		$ 120.0
Operating lease ROU asset		$ 134.0	$ 162.0
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]		Other assets	Other assets
Operating lease liability		$ 140.0	$ 170.0
Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration]		Other liabilities	Other liabilities
Finance Lease, Right-of-Use Asset, Accumulated Amortization		$ 436.0	$ 398.0
Weighted average discount rate, operating lease		2.50%	3.10%
Weighted average remaining operating lease term		5 years	6 years
Operating lease expense		$ 41.0	$ 42.0	$ 46.0
Finance lease, net book value		$ 37.0	$ 75.0
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]		Other assets	Other assets
Weighted average discount rate, finance lease		1.40%	2.20%
Weighted average remaining finance lease term		1 year	2 years
Finance Lease, Liability		$ 175.0	$ 234.0
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]		Other liabilities	Other liabilities
Number of leases not yet commenced | contract		1
Loss contingency accrual, insurance-related assessment, premium tax offset		$ (7.0)	$ (9.0)
Subsequent Event [Member]
Loss Contingencies [Line Items]
Litigation Settlement, Amount Awarded to Other Party	$ 92.5