Financial Derivatives (Total Derivatives) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Derivative [Line Items]
Derivative, notional amount	$ 522,114	$ 466,707
Derivative asset, fair value	7,035	6,533
Derivative liability, fair value	4,781	2,756
Derivative asset, fair value offset amount	1,027	720
Derivative liability, fair value offset amount	1,027	720
Derivative asset, cash collateral	757	1,434
Derivative liability, cash collateral	2,403	1,452
Derivative asset, net fair value	5,251	4,379
Derivative liability, net fair value	1,351	584
Commodity contracts:
Derivative [Line Items]
Derivative asset, fair value	2,521	411
Derivative liability, fair value	2,536	384
Derivative asset, cash collateral	28	4
Derivative liability, cash collateral	1,511	103
Foreign exchange contracts and other
Derivative [Line Items]
Derivative asset, fair value	244	271
Derivative liability, fair value	530	590
Derivative asset, cash collateral	6	4
Derivative liability, cash collateral	79	170
Designated as Hedging Instruments under GAAP
Derivative [Line Items]
Derivative, notional amount	68,003	48,103
Derivative asset, fair value	13	14
Derivative liability, fair value	41	22
Designated as Hedging Instruments under GAAP \| Fair value hedges \| Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	24,837	24,153
Designated as Hedging Instruments under GAAP \| Cash flow hedges \| Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	42,018	22,875
Derivative asset, fair value	12	14
Derivative liability, fair value	38
Designated as Hedging Instruments under GAAP \| Net investment hedges \| Foreign exchange contracts:
Derivative [Line Items]
Derivative, notional amount	1,148	1,075
Derivative asset, fair value	1
Derivative liability, fair value	3	22
Not Designated as Hedging Instrument under GAAP
Derivative [Line Items]
Derivative, notional amount	454,111	418,604
Derivative asset, fair value	7,022	6,519
Derivative liability, fair value	4,740	2,734
Not Designated as Hedging Instrument under GAAP \| Mortgage Banking \| Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	65,094	66,471
Derivative asset, fair value	136	158
Derivative liability, fair value	65	79
Not Designated as Hedging Instrument under GAAP \| Mortgage Banking \| Swaps \| Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	33,994	50,511
Derivative asset, fair value
Not Designated as Hedging Instrument under GAAP \| Mortgage Banking \| Futures \| Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	3,666	2,841
Not Designated as Hedging Instrument under GAAP \| Mortgage Banking \| Mortgage-backed commitments \| Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	13,702	11,288
Derivative asset, fair value	98	147
Derivative liability, fair value	54	77
Not Designated as Hedging Instrument under GAAP \| Mortgage Banking \| Other \| Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	13,732	1,831
Derivative asset, fair value	38	11
Derivative liability, fair value	11	2
Not Designated as Hedging Instrument under GAAP \| Customer Contracts
Derivative [Line Items]
Derivative, notional amount	376,235	341,202
Derivative asset, fair value	6,835	6,357
Derivative liability, fair value	4,330	2,330
Not Designated as Hedging Instrument under GAAP \| Customer Contracts \| Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	335,755	305,663
Derivative asset, fair value	4,122	5,679
Derivative liability, fair value	1,612	1,703
Not Designated as Hedging Instrument under GAAP \| Customer Contracts \| Commodity contracts:
Derivative [Line Items]
Derivative, notional amount	12,485	8,919
Derivative asset, fair value	2,521	411
Derivative liability, fair value	2,536	384
Not Designated as Hedging Instrument under GAAP \| Customer Contracts \| Foreign exchange contracts and other
Derivative [Line Items]
Derivative, notional amount	27,995	26,620
Derivative asset, fair value	192	267
Derivative liability, fair value	182	243
Not Designated as Hedging Instrument under GAAP \| Customer Contracts \| Swaps \| Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	304,724	280,125
Derivative asset, fair value	3,961	5,475
Derivative liability, fair value	1,508	1,601
Not Designated as Hedging Instrument under GAAP \| Customer Contracts \| Swaps \| Commodity contracts:
Derivative [Line Items]
Derivative, notional amount	9,249	6,149
Derivative asset, fair value	2,099	350
Derivative liability, fair value	2,114	323
Not Designated as Hedging Instrument under GAAP \| Customer Contracts \| Futures \| Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	1,006	1,235
Not Designated as Hedging Instrument under GAAP \| Customer Contracts \| Mortgage-backed commitments \| Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	4,692	4,178
Derivative asset, fair value	18	11
Derivative liability, fair value	16	14
Not Designated as Hedging Instrument under GAAP \| Customer Contracts \| Other \| Interest Rate Contracts
Derivative [Line Items]
Derivative, notional amount	25,333	20,125
Derivative asset, fair value	143	193
Derivative liability, fair value	88	88
Not Designated as Hedging Instrument under GAAP \| Customer Contracts \| Other \| Commodity contracts:
Derivative [Line Items]
Derivative, notional amount	3,236	2,770
Derivative asset, fair value	422	61
Derivative liability, fair value	422	61
Not Designated as Hedging Instrument under GAAP \| Other Risk Management Activity \| Foreign exchange contracts and other
Derivative [Line Items]
Derivative, notional amount	12,782	10,931
Derivative asset, fair value	51	4
Derivative liability, fair value	$ 345	$ 325

Fair value of the gross assets less the offsetting amount of derivative assets.

No definition available.

Name:	pnc_DerivativeAssetFairValueNetOfOffsetAmount
Namespace Prefix:	pnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of setoff associated with the entity's recognized derivative assets with corresponding derivative liability amounts subject to an enforceable master netting agreement or similar agreement.

+ References

No definition available.

+ Details

Name:	pnc_DerivativeAssetSetoffRightAmount
Namespace Prefix:	pnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value of the gross liabilities less the amount of offsetting amount of derivative liabilities.

+ References

No definition available.

+ Details

Name:	pnc_DerivativeLiabilityFairValueNetOfOffsetLiabilities
Namespace Prefix:	pnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of setoff associated with the entity's recognized derivative liabilities with corresponding derivative asset amounts subject to an enforceable master netting agreement or similar agreement.

+ References

No definition available.

+ Details

Name:	pnc_DerivativeLiabilitySetoffRightAmount1
Namespace Prefix:	pnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of obligation to return cash collateral under master netting arrangements offset against derivative assets.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=117331979&loc=d3e41228-113958

+ Details

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

- Definition

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226000-175313

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4D
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=121570589&loc=SL51823488-111719

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (a),(c)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5624163-113959

+ Details

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

- Definition

Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4D
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=121570589&loc=SL51823488-111719

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (a),(c)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5624163-113959

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226000-175313

+ Details

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

- Definition

Amount of right to receive cash collateral under master netting arrangements offset against derivative liabilities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=117331979&loc=d3e41228-113958

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

+ Details

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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959

+ Details

Name:	us-gaap_DerivativeNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_CommodityContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=pnc_ForeignExchangeAndOtherContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_HedgingDesignationAxis=us-gaap_DesignatedAsHedgingInstrumentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_FairValueHedgingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_CashFlowHedgingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_NetInvestmentHedgingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForeignExchangeContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_HedgingDesignationAxis=us-gaap_NondesignatedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_MortgageBankingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_CustomerContractsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=pnc_OtherRiskManagementActivityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: