Fair Value Hierarchy for Financial Instruments Not Recorded at Fair Value (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Carrying Amount
Assets:
Cash and cash equivalents	$ 7,245
Cash and investments segregated and on deposit for regulatory purposes	19,417
Receivables from brokers, dealers, and clearing organizations	317
Receivables from brokerage clients - net	11,952
Securities held to maturity	15,506	15,108
Loans to banking clients - net	9,837	9,812
Loans held for sale	2	70
Other assets	62
Total	64,338
Liabilities:
Deposits from banking clients	66,257
Payables to brokers, dealers, and clearing organizations	1,332
Payables to brokerage clients	31,833
Accrued expenses and other liabilities	501
Long-term debt	1,999	2,001
Total	101,922
Carrying Amount | Residential real estate mortgages
Assets:
Loans to banking clients - net	5,640
Carrying Amount | Home equity lines of credit
Assets:
Loans to banking clients - net	3,391
Carrying Amount | Personal loans secured by securities
Assets:
Loans to banking clients - net	787
Carrying Amount | Other
Assets:
Loans to banking clients - net	19
Carrying Amount | U.S. agency residential mortgage-backed securities
Assets:
Securities held to maturity	15,227
Carrying Amount | Other securities
Assets:
Securities held to maturity	279
Fair Value
Assets:
Cash and cash equivalents	7,245
Cash and investments segregated and on deposit for regulatory purposes	19,417
Receivables from brokers, dealers, and clearing organizations	317
Receivables from brokerage clients - net	11,952
Securities held to maturity	16,009	15,539
Loans to banking clients - net	9,916	9,671
Loans held for sale	3	73
Other assets	62
Total	64,921
Liabilities:
Deposits from banking clients	66,257
Payables to brokers, dealers, and clearing organizations	1,332
Payables to brokerage clients	31,833
Accrued expenses and other liabilities	501
Long-term debt	2,189	2,159
Total	102,112
Fair Value | Residential real estate mortgages
Assets:
Loans to banking clients - net	5,742
Fair Value | Home equity lines of credit
Assets:
Loans to banking clients - net	3,368
Fair Value | Personal loans secured by securities
Assets:
Loans to banking clients - net	787
Fair Value | Other
Assets:
Loans to banking clients - net	19
Fair Value | U.S. agency residential mortgage-backed securities
Assets:
Securities held to maturity	15,730
Fair Value | Other securities
Assets:
Securities held to maturity	279
Fair Value | Significant Other Observable Inputs (Level 2)
Assets:
Cash and cash equivalents	7,245
Cash and investments segregated and on deposit for regulatory purposes	19,417
Receivables from brokers, dealers, and clearing organizations	317
Receivables from brokerage clients - net	11,952
Securities held to maturity	16,009
Loans to banking clients - net	9,916
Loans held for sale	3
Other assets	62
Total	64,921
Liabilities:
Deposits from banking clients	66,257
Payables to brokers, dealers, and clearing organizations	1,332
Payables to brokerage clients	31,833
Accrued expenses and other liabilities	501
Long-term debt	2,189
Total	102,112
Fair Value | Significant Other Observable Inputs (Level 2) | Residential real estate mortgages
Assets:
Loans to banking clients - net	5,742
Fair Value | Significant Other Observable Inputs (Level 2) | Home equity lines of credit
Assets:
Loans to banking clients - net	3,368
Fair Value | Significant Other Observable Inputs (Level 2) | Personal loans secured by securities
Assets:
Loans to banking clients - net	787
Fair Value | Significant Other Observable Inputs (Level 2) | Other
Assets:
Loans to banking clients - net	19
Fair Value | Significant Other Observable Inputs (Level 2) | U.S. agency residential mortgage-backed securities
Assets:
Securities held to maturity	15,730
Fair Value | Significant Other Observable Inputs (Level 2) | Other securities
Assets:
Securities held to maturity	$ 279