Employee Benefit Plans (Pension Plan Assets Fair Value Hierarchy) (Details) - PNC Pension Plan - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 6,073	$ 5,654
Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,757	1,658
Level 1 | Money market funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	572	456
Level 1 | U.S. government and agency securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	446	582
Level 1 | Common stock
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	738	620
Level 1 | Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1
Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,360	1,176
Level 2 | Interest bearing cash
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		1
Level 2 | U.S. government and agency securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	126	135
Level 2 | Corporate debt
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	730	660
Level 2 | Common stock
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		1
Level 2 | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	290	253
Level 2 | Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	214	126
Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4	8
Level 3 | U.S. government and agency securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		1
Level 3 | Corporate debt
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3	3
Level 3 | Common stock
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1	4
Fair Value, Inputs, Level 1, 2 and 3 | Interest bearing cash
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		1
Fair Value, Inputs, Level 1, 2 and 3 | Money market funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	572	456
Fair Value, Inputs, Level 1, 2 and 3 | U.S. government and agency securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	572	718
Fair Value, Inputs, Level 1, 2 and 3 | Corporate debt
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	733	663
Fair Value, Inputs, Level 1, 2 and 3 | Common stock
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	739	625
Fair Value, Inputs, Level 1, 2 and 3 | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	290	253
Fair Value, Inputs, Level 1, 2 and 3 | Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	215	126
Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 2,952	$ 2,812