Bank Loans and Related Allowance for Credit Losses (Convert to Amortizing Loans) (Details) - HELOCs [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
HELOCs converted to amortizing loans	$ 9	$ 13	$ 25	$ 41
Converted to an amortizing loan by period end	416		416
Within 1 year	37		37
1 year – 3 years	83		83
3 years – 5 years	112		112
5 years	266		266
Total	$ 914		$ 914