Employee Benefit Plans (Pension Plan Assets Fair Value Hierarchy) (Details) - PNC Pension Plan - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 4,963	$ 5,253	$ 4,617
Interest Bearing Cash
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	9	11
Money Market Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	149	339
US government and agency securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	642	338
Corporate Debt
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	586	583
Common Stock
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	629	804
Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	236	271
Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	50	77
Investments measured at net asset value
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,662	2,830
Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,295	1,374
Level 1 | Interest Bearing Cash
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	7	10
Level 1 | Money Market Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	149	339
Level 1 | US government and agency securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	512	233
Level 1 | Common Stock
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	623	791
Level 1 | Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4	1
Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	996	1,037
Level 2 | Interest Bearing Cash
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2	1
Level 2 | US government and agency securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	130	105
Level 2 | Corporate Debt
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	580	578
Level 2 | Common Stock
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6	13
Level 2 | Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	236	271
Level 2 | Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	42	69
Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	10	12
Level 3 | Corporate Debt
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6	5
Level 3 | Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 4	$ 7