Investment Securities (Amortized Cost, Gross Unrealized Gains and Losses, and Fair Value of Securities Available for Sale and Held to Maturity Securities) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Available for sale securities:
Amortized Cost	$ 56,149	$ 66,735
Gross Unrealized Gains	399	72
Gross Unrealized Losses	65	229
Fair Value	56,483	66,578
Held to maturity securities:
Amortized Cost	140,194	144,009
Gross Unrealized Gains	2,247	330
Gross Unrealized Losses	278	2,301
Fair Value	142,163	142,038
U.S. agency mortgage-backed securities [Member]
Available for sale securities:
Amortized Cost	40,179	25,594
Gross Unrealized Gains	299	44
Gross Unrealized Losses	47	82
Fair Value	40,431	25,556
Held to maturity securities:
Amortized Cost	114,276	118,064
Gross Unrealized Gains	1,974	217
Gross Unrealized Losses	238	2,188
Fair Value	116,012	116,093
U.S. Treasury securities [Member]
Available for sale securities:
Amortized Cost	5,034	18,410
Gross Unrealized Gains	3	0
Gross Unrealized Losses	10	108
Fair Value	5,027	18,302
Held to maturity securities:
Amortized Cost	224	223
Gross Unrealized Gains	6	0
Gross Unrealized Losses	0	6
Fair Value	230	217
Asset-backed securities [Member]
Available for sale securities:
Amortized Cost	4,773	10,086
Gross Unrealized Gains	35	14
Gross Unrealized Losses	7	15
Fair Value	4,801	10,085
Held to maturity securities:
Amortized Cost	18,323	18,502
Gross Unrealized Gains	74	83
Gross Unrealized Losses	38	39
Fair Value	18,359	18,546
Corporate debt securities [Member]
Available for sale securities:
Amortized Cost	4,630	7,477
Gross Unrealized Gains	57	10
Gross Unrealized Losses	1	20
Fair Value	4,686	7,467
Held to maturity securities:
Amortized Cost	4,659	4,477
Gross Unrealized Gains	58	2
Gross Unrealized Losses	2	47
Fair Value	4,715	4,432
Certificates of deposit [Member]
Available for sale securities:
Amortized Cost	1,000	3,682
Gross Unrealized Gains	4	4
Gross Unrealized Losses	0	1
Fair Value	1,004	3,685
Held to maturity securities:
Amortized Cost	200	200
Gross Unrealized Gains	0	1
Gross Unrealized Losses	0	0
Fair Value	200	201
U.S. agency notes [Member]
Available for sale securities:
Amortized Cost		900
Gross Unrealized Gains		0
Gross Unrealized Losses		2
Fair Value		898
U.S. state and municipal securities [Member]
Held to maturity securities:
Amortized Cost	1,306	1,327
Gross Unrealized Gains	107	24
Gross Unrealized Losses	0	3
Fair Value	1,413	1,348
Commercial paper [Member]
Available for sale securities:
Amortized Cost	520	522
Gross Unrealized Gains	1	0
Gross Unrealized Losses	0	0
Fair Value	521	522
Available-for-sale securities, current	900	4,900
Foreign government agency securities [Member]
Available for sale securities:
Amortized Cost		50
Gross Unrealized Gains		0
Gross Unrealized Losses		1
Fair Value		49
Held to maturity securities:
Amortized Cost	50	50
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	1
Fair Value	50	49
Non-agency commercial mortgage-backed securities [Member]
Available for sale securities:
Amortized Cost	13	14
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	13	14
Held to maturity securities:
Amortized Cost	1,136	1,156
Gross Unrealized Gains	28	3
Gross Unrealized Losses	0	17
Fair Value	1,164	1,142
Other [Member]
Held to maturity securities:
Amortized Cost	20	10
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	$ 20	$ 10
Federal Family Education Loan Program (FFELP) Guaranteed Loans [Member]
Held to maturity securities:
Asset-backed securities percentage	43.00%	36.00%
Collateralized Credit Card Securities [Member]
Held to maturity securities:
Asset-backed securities percentage	42.00%	42.00%
Corporate debt securities issued by financial services industry [Member]
Held to maturity securities:
AFS and HTM securities percentage	35.00%	26.00%
Corporate debt securities, information technology [Member]
Held to maturity securities:
AFS and HTM securities percentage	18.00%	18.00%

Concentration Risk, Asset-Backed Securities

No definition available.

Name:	schw_ConcentrationRiskAssetBackedSecurities
Namespace Prefix:	schw_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Concentration Risk, Available For Sale And Held To Maturity Securities

+ References

No definition available.

+ Details

Name:	schw_ConcentrationRiskAvailableForSaleAndHeldToMaturitySecurities
Namespace Prefix:	schw_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563

+ Details

Name:	us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563

+ Details

Name:	us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=118942338&loc=SL82898722-210454

+ Details

Name:	us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=118942338&loc=SL82898722-210454

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118954083&loc=d3e26610-111562

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesDebtSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), classified as current.

+ References

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118954083&loc=d3e26610-111562

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27232-111563

+ Details

Name:	us-gaap_HeldToMaturitySecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27232-111563

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27232-111563

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value of investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27232-111563

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_AssetBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CertificatesOfDepositMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CommercialPaperMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_ForeignGovernmentDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=schw_CommercialMortageBackedSecuritiesIssuedByPrivateEnterprisesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_OtherDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_FederalFamilyEducationLoanProgramFfelpGuaranteedLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CollateralizedCreditCardSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=schw_CorporateDebtSecuritiesIssuedByFinancialServicesIndustryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=schw_CorporateDebtSecuritiesInformationTechnologyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: