Leases (Narrative) (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019 USD ($) Branches numberOfBranches	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) Branches numberOfBranches	Jun. 30, 2018 USD ($)
Leases [Abstract]
Number of Branches | Branches	432		432
Number of Branches Owned | numberOfBranches	277		277
Number of Branches Leased | numberOfBranches	155		155
Operating Lease, Right-of-Use Asset	$ 232		$ 232
Finance Lease, Right-of-Use Asset	1		1
Operating Lease, Liability	$ 251		$ 251
Operating Lease, Weighted Average Remaining Lease Term	9 years 3 months 18 days		9 years 3 months 18 days
Finance Lease, Weighted Average Remaining Lease Term	10 months 24 days		10 months 24 days
Operating Lease, Weighted Average Discount Rate, Percent	3.20%		3.20%
Finance Lease, Weighted Average Discount Rate, Percent	12.60%		12.60%
Operating Lease, Cost	$ 12		$ 24
Variable Lease, Cost	13		26
Lease, Cost	25		50
Operating Cash Disbursement From Operating Leases	12		24
Lease Liabilities, Maturity One Year	32		32
Liabilities	47		47
Lease Liabilities, Maturity Year Three	42		42
Lease Liabilities, Maturity Year Four	37		37
Lease Liabilities, Maturity Year Five	31		31
Lease Liabilities, Maturity Year Thereafter	116		116
Lease Liabilities, Maturity	305		305
Operating Lease, Lease Income	3	$ 3	6	$ 5
Sales-type and Direct Financing Leases, Lease Receivable	337	358	337	358
Sales-type and Direct Financing Leases, Profit (Loss)	$ 3	$ 3	$ 7	$ 7