Fair Values of Assets and Liabilities (Fair Value Hierarchy for Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Other securities owned	$ 533	$ 516
Securities available for sale	65,646	54,783
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	2,328	2,174
Investments segregated and on deposit for rugulatory purposes	7,947	6,311
Other securities owned	533	516
Securities available for sale	65,646	54,783
Total	76,454	63,784
Fair Value, Measurements, Recurring [Member] | Money market funds [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	1,968	2,142
Fair Value, Measurements, Recurring [Member] | Commercial paper [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	360	32
Fair Value, Measurements, Recurring [Member] | Certificates of deposit [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Investments segregated and on deposit for rugulatory purposes	3,430	4,125
Securities available for sale	1,683	1,534
Fair Value, Measurements, Recurring [Member] | U.S. Government securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Investments segregated and on deposit for rugulatory purposes	4,517	2,186
Fair Value, Measurements, Recurring [Member] | Schwab Funds money market funds [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Other securities owned	261	224
Fair Value, Measurements, Recurring [Member] | Equity and bond mutual funds [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Other securities owned	205	215
Fair Value, Measurements, Recurring [Member] | State and municipal debt obligations [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Other securities owned	50	51
Fair Value, Measurements, Recurring [Member] | Equity, U.S. Government and corporate debt, and other securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Other securities owned	17	26
Fair Value, Measurements, Recurring [Member] | U.S. agency mortgage-backed securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	22,149	18,717
Fair Value, Measurements, Recurring [Member] | Asset-backed securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	21,485	19,366
Fair Value, Measurements, Recurring [Member] | Corporate debt securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	10,747	8,045
Fair Value, Measurements, Recurring [Member] | U.S. Treasury securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	5,704	2,994
Fair Value, Measurements, Recurring [Member] | U.S. agency notes [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	3,150	3,795
Fair Value, Measurements, Recurring [Member] | U.S. state and municipal securities
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	424
Fair Value, Measurements, Recurring [Member] | Non-agency commercial mortgage-backed securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	299	317
Fair Value, Measurements, Recurring [Member] | Other securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	5	15
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	1,968	2,142
Other securities owned	467	441
Total	2,435	2,583
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Money market funds [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	1,968	2,142
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Schwab Funds money market funds [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Other securities owned	261	224
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Equity and bond mutual funds [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Other securities owned	205	215
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Equity, U.S. Government and corporate debt, and other securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Other securities owned	1	2
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	9,650	9,189
Investments segregated and on deposit for rugulatory purposes	11,647	14,466
Total	103,961	88,151
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	360	32
Investments segregated and on deposit for rugulatory purposes	7,947	6,311
Other securities owned	66	75
Securities available for sale	65,646	54,783
Total	74,019	61,201
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Commercial paper [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	360	32
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Certificates of deposit [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Investments segregated and on deposit for rugulatory purposes	3,430	4,125
Securities available for sale	1,683	1,534
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | U.S. Government securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Investments segregated and on deposit for rugulatory purposes	4,517	2,186
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | State and municipal debt obligations [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Other securities owned	50	51
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Equity, U.S. Government and corporate debt, and other securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Other securities owned	16	24
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | U.S. agency mortgage-backed securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	22,149	18,717
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Asset-backed securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	21,485	19,366
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Corporate debt securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	10,747	8,045
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | U.S. Treasury securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	5,704	2,994
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | U.S. agency notes [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	3,150	3,795
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | U.S. state and municipal securities
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	424
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Non-agency commercial mortgage-backed securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	299	317
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Other securities [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	$ 5	$ 15