Segment Information (Financial Information for Reportable Segments) (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net Revenues:
Net interest revenue										$ 4,282	$ 3,322	$ 2,525
Asset management and administration fees	[1]									3,392	3,055	2,650
Trading revenue										654	825	866
Other										290	271	328
Provision for loan losses										0	5	11
Total net revenues		$ 2,242	$ 2,165	$ 2,130	$ 2,081	$ 1,972	$ 1,914	$ 1,828	$ 1,764	8,618	7,478	6,380
Total Expenses Excluding Interest		$ 1,289	$ 1,220	$ 1,221	$ 1,238	$ 1,148	$ 1,120	$ 1,108	$ 1,109	4,968	4,485	4,101
Income before taxes on income										3,650	2,993	2,279
Capital expenditures										412	353	285
Depreciation and amortization										269	234	224
Investor Services [Member]
Net Revenues:
Net interest revenue										3,231	2,591	2,133
Asset management and administration fees										2,344	2,093	1,837
Trading revenue										408	524	556
Other										217	199	234
Provision for loan losses										0	4	11
Total net revenues										6,200	5,411	4,771
Total Expenses Excluding Interest										3,725	3,380	3,090
Income before taxes on income										2,475	2,031	1,681
Capital expenditures										265	234	195
Depreciation and amortization										203	180	171
Advisor Services [Member]
Net Revenues:
Net interest revenue										1,051	731	392
Asset management and administration fees										1,048	962	813
Trading revenue										246	301	310
Other										73	72	94
Provision for loan losses										0	1	0
Total net revenues										2,418	2,067	1,609
Total Expenses Excluding Interest										1,243	1,105	1,011
Income before taxes on income										1,175	962	598
Capital expenditures										147	119	90
Depreciation and amortization										$ 66	$ 54	$ 53

[1] Includes fee waivers of $10 million, $224 million, and $672 million during the years ended December 31, 2017, 2016, and 2015, respectively, relating to Schwab-sponsored money market funds.