Loans to Banking Clients and Related Allowance for Loan Losses (Composition of Loans to Banking Clients by Loan Segment) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans to banking clients	$ 12,639	$ 12,467
Allowance for loan losses	(48)	(48)	(59)	(56)
Total loans to banking clients - net	12,591	12,419
Residential real estate mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans to banking clients	8,050	8,006
Allowance for loan losses	(33)	(34)	(40)	(36)
Home equity lines of credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans to banking clients	3,018	3,041
Allowance for loan losses	(15)	(14)	(19)	(20)
Personal loans secured by securities [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans to banking clients	1,536	1,384
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans to banking clients	$ 35	$ 36