Leases (Narrative) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2021 USD ($)
Lessee, Lease, Description [Line Items]
Lessee, operating lease, lease not yet commenced, amount	$ 13
Minimum
Lessee, Lease, Description [Line Items]
Lessee, operating lease, term of contract (years)	10 years
Maximum
Lessee, Lease, Description [Line Items]
Lessee, operating lease, term of contract (years)	25 years
Office Space
Lessee, Lease, Description [Line Items]
Lease obligations, percent	99.00%