Loans to Banking Clients and Related Allowance for Loan Losses (Delinquency Analysis by Loan Class) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 13,392		$ 12,407
30-59 days past due	11		6
60-89 days past due	3		6
>90 days past due and other nonaccrual loans	35		48
Total past due	49		60
Total loans	13,441	[1]	12,467	[1]
Residential real estate mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	8,092		7,962
30-59 days past due	9		4
60-89 days past due	2		4
>90 days past due and other nonaccrual loans	24		36
Total past due	35		44
Total loans	8,127		8,006
Home equity lines of credit [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	2,942		3,025
30-59 days past due	1		2
60-89 days past due	1		2
>90 days past due and other nonaccrual loans	11		12
Total past due	13		16
Total loans	2,955		3,041
Personal loans secured by securities [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	2,320		1,384
Total loans	2,320		1,384
Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	38		36
30-59 days past due	1
Total past due	1
Total loans	$ 39		$ 36

[1] Loans are evaluated for impairment by loan segment.