Financial Derivatives (Narrative) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Derivative [Line Items]
Cash and securities held to collateralize net derivative assets	$ 1,500,000,000		$ 1,500,000,000
Cash and securities pledged to collateralize net derivative liabilities	2,700,000,000		2,700,000,000
Derivative, net liability position, aggregate fair value	2,600,000,000		2,600,000,000
Collateral already posted, aggregate fair value	2,200,000,000		2,200,000,000
Maximum amount of collateral PNC would have been required to post if the credit-risk-related contingent features underlying these agreements had been triggered	400,000,000		400,000,000
Cash flow hedges | Interest Rate Contracts
Derivative [Line Items]
Cash flow hedge gain (loss) to be reclassified within twelve months			330,000,000
Cash flow hedge gain (loss) to be reclassified within twelve months, net of tax			$ 254,000,000
Maximum length of time hedged in cash flow hedge			10 years
Net investment hedges | Foreign exchange contracts:
Derivative [Line Items]
Derivative instruments, gain (loss) reclassified from accumulated oci into income, effective portion, net	(4,000,000)	$ 5,000,000	$ (12,000,000)	$ 80,000,000
Gain loss from components excluded from assessment of net investment hedge effectiveness net	$ 0	$ 0	$ 0	$ 0