Summary of Significant Accounting Policies (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Land, Buildings, Equipment and Software
Land, buildings, equipment and software, net of accumulated depreciation	$ 753,000,000	$ 774,000,000
Accumulated depreciation	1,200,000,000	1,100,000,000
Depreciation and amortization expense for the year	152,000,000	143,000,000	160,000,000
Principles of Consolidation
Minimum percentage of voting interest required to be held to consolidate an entity	50.00%
Maximum percentage of voting interest required to be held to be accounted for, under the cost method	20.00%
Financing Receivables
Period of non payment after which a loan is placed on nonaccrual status	90 days
Period for charging off revolving unsecured consumer lines	180 days
Period for charging off closed-end consumer loans, other than loans secured by one to four family properties	120 days
Restricted and segregated cash and investments
Restricted cash	107,000,000	79,000,000
Amounts segregated under federal and other regulations	2,400,000,000	1,700,000,000
Deferred Acquisition Costs
Mean reversion process, period	5 years
Income Taxes
Maximum period for recognizing capital losses	5 years
Valuation allowance	$ 16,000,000	$ 5,000,000
Maximum
Equity Method Investments
Percentage of voting interest required to be held to be accounted for under the equity method	50.00%
Land, Buildings, Equipment and Software
Amortization periods	39 years
Minimum
Equity Method Investments
Percentage of voting interest required to be held to be accounted for under the equity method	20.00%
Land, Buildings, Equipment and Software
Amortization periods	3 years