The Charles Schwab Corporation – Parent Company Only Financial Statements (Condensed Statements of Cash Flows) (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
Cash Flows from Operating Activities
Net income	$ 597	$ 618	$ 575	$ 564	$ 522	$ 503	$ 452	$ 412	$ 2,354	$ 1,889	$ 1,447
Adjustments to reconcile net income to net cash provided by operating activities:
Other									51	9	(4)
Net change in:
Other securities owned									(90)	84	(17)
Other assets									(177)	(93)	(98)
Accrued expenses and other liabilities									421	167	304
Net cash provided by operating activities									1,263	2,662	1,246
Cash Flows from Investing Activities
Purchases of available for sale securities									(15,033)	(29,248)	(21,351)
Proceeds from sales of available for sale securities									8,617	5,537	2,424
Principal payments on available for sale securities									9,095	11,903	7,340
Purchases of held to maturity securities									(32,925)	(31,162)	(19,303)
Other investing activities									(59)	(39)	(35)
Net cash used for investing activities									(20,473)	(38,775)	(28,623)
Cash Flows from Financing Activities
Issuance of long-term debt									2,129	0	1,346
Repayment of long-term debt									(257)	(7)	(357)
Net proceeds from preferred stock offerings									492	1,316	581
Redemption of preferred stock									(485)	0	0
Dividends paid									(592)	(486)	(387)
Proceeds from stock options exercised and other									171	144	90
Other financing activities									(45)	44	32
Net cash provided by financing activities									22,599	34,963	27,992
Increase (Decrease) in Cash and Cash Equivalents									3,389	(1,150)	615
Cash and Cash Equivalents at Beginning of Year				10,828				11,978	10,828	11,978	11,363
Cash and Cash Equivalents at End of Year	14,217				10,828				14,217	10,828	11,978
Parent Company [Member]
Cash Flows from Operating Activities
Net income									2,354	1,889	1,447
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in undistributed earnings of subsidiaries									(1,479)	(1,690)	(1,287)
Other									5	(37)	(31)
Net change in:
Other securities owned									(1)	(10)	9
Other assets									(26)	(27)	(32)
Accrued expenses and other liabilities									44	30	4
Net cash provided by operating activities									897	155	110
Cash Flows from Investing Activities
Due from (to) subsidiaries — net									(374)	95	93
Increase in investments in subsidiaries									(342)	(1,547)	(611)
Repayments (Advances) of subordinated loan to CS&Co									0	465	(150)
Purchases of available for sale securities									(201)	(2)	(842)
Proceeds from sales of available for sale securities									197	2	200
Principal payments on available for sale securities									0	0	75
Purchases of held to maturity securities									0	0	(223)
Other investing activities									(6)	(4)	0
Net cash used for investing activities									(726)	(991)	(1,458)
Cash Flows from Financing Activities
Issuance of long-term debt									2,129	0	1,346
Repayment of long-term debt									(250)	0	(350)
Net proceeds from preferred stock offerings									492	1,316	581
Redemption of preferred stock									(485)	0	0
Dividends paid									(592)	(486)	(387)
Proceeds from stock options exercised and other									171	144	90
Other financing activities									0	44	32
Net cash provided by financing activities									1,465	1,018	1,312
Increase (Decrease) in Cash and Cash Equivalents									1,636	182	(36)
Cash and Cash Equivalents at Beginning of Year				$ 1,189				$ 1,007	1,189	1,007	1,043
Cash and Cash Equivalents at End of Year	$ 2,825				$ 1,189				$ 2,825	$ 1,189	$ 1,007