Total Equity and Other Comprehensive Income (Other Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net Unrealized Gains Losses on Non Otti Securities [Abstract]
Increase in net unrealized gains (losses) on non-OTTI securities	$ (645)	$ 67
Less: Net gains (losses) realized as a yield adjustment reclassified to investment securities in interest income, before tax	4	5
Less: Net gains (losses) realized on sales of non-OTTI securities reclassified to noninterest income, before tax	(3)	(7)
Net unrealized gains (losses) on non-OTTI securities	(646)	69
Other Comprehensive Income (Loss), Non Otti Securities Adjustment, Tax	150	(25)
Net unrealized gains (losses) on non-OTTI securities, Activity, After Tax	(496)	44
Net Unrealized Gains Losses On Otti Securities [Abstract]
Increase in net unrealized gains (losses) on OTTI securities, Pretax	14	37
Less: Net gains (losses) realized on sales of securities reclassified to noninterest income		(2)
Net unrealized gains (losses) on OTTI securities	14	35
Net unrealized gains (losses) on OTTI securities, tax	(4)	(13)
Net unrealized gains (losses) on OTTI securities, Activity, After Tax	10	22
Net unrealized gains (losses) on cash flow hedge derivatives [Abstract]
Increase in net unrealized gains (losses) on cash flow hedge derivatives, Pretax	(161)	(22)
Less: Net gains (losses) realized as a yield adjustment reclassified to loan interest income, Before Tax	26	46
Less: Net gains (losses) realized as a yield adjustment reclassified to investment securities interest income, Before Tax	4	6
Less: Net gains (losses) realized on sales of securities reclassified to noninterest income	2	3
Net unrealized gains (losses) on cash flow hedge derivatives, Before Tax	(193)	(77)
Net unrealized gains (losses) on cash flow hedge derivatives, tax	44	28
Net unrealized gains (losses) on cash flow hedge derivatives, Net of tax, Total	(149)	(49)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax [Abstract]
Net pension and other postretirement benefit plan activity, Before tax	61	(74)
Amortization of actuarial loss (gain) reclassified to other noninterest expense, Before tax	1	13
Amortization of prior service cost (credit) reclassified to other noninterest expense, Before tax	1	(1)
Pension and other postretirement benefit plan adjustments, net activity, Pre-Tax	63	(62)
Pension and other postretirement benefit plan adjustments, net activity, Tax	(15)	23
Pension and other postretirement benefit plan adjustments, net activity, After Tax	48	(39)
Other Comprehensive Income Other Adjustments [Abstract]
PNC's portion of BlackRock's OCI, Before tax	22	2
Net investment hedge derivatives, Before tax	(39)	(14)
Foreign Currency Transaction and Translation Adjustment, before Tax	44	16
Total Other, net activity, Before tax	27	4
Effect of income taxes	3	4
Total Other, net activity, After tax	30	8
Other comprehensive income (loss), before tax and net of reclassifications into Net income	(735)	(31)
Other Comprehensive Income (Loss), Tax	178	17
Other comprehensive income (loss), after tax and net of reclassifications into Net income	$ (557)	$ (14)