Bank Loans and Related Allowance for Loan Losses (Delinquency Analysis by Loan Class) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 13,596		$ 13,392
30-59 days past due	12		11
60-89 days past due	2		3
>90 days past due and other nonaccrual loans	31		35
Total past due and other nonaccrual loans	45		49
Total loans	13,641	[1]	13,441	[1]
Residential Real Estate Mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	8,140		8,092
30-59 days past due	9		9
60-89 days past due	1		2
>90 days past due and other nonaccrual loans	22		24
Total past due and other nonaccrual loans	32		35
Total loans	8,172		8,127
Home Equity Loans and Lines of Credit [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	2,865		2,942
30-59 days past due	3		1
60-89 days past due	1		1
>90 days past due and other nonaccrual loans	9		11
Total past due and other nonaccrual loans	13		13
Total loans	2,878		2,955
Personal loans secured by securities [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	2,549		2,320
Total loans	2,549		2,320
Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	42		38
30-59 days past due			1
Total past due and other nonaccrual loans			1
Total loans	$ 42		$ 39

[1] All loans are evaluated for impairment by loan segment.