v3.20.4
Capital Stock - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
May 15, 2015
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Oct. 06, 2020
Schedule of Capitalization, Equity [Line Items]          
Common stock, par value   $ 0.01 $ 0.01    
Preferred stock, par value   $ 0.01 0.01    
Preferred stock, shares outstanding   0     0
Dividends, cash per common or preferred share   $ 14.52 $ 13.20 $ 12.02  
Aggregate dividends   $ 2,260 $ 2,096 $ 1,968  
Common shares repurchased, value   $ 1,512 $ 1,666 $ 1,660  
Share Repurchase Program [Member]          
Schedule of Capitalization, Equity [Line Items]          
Common shares repurchased   800,000      
Common shares repurchased, value   $ 412      
Shares authorized to be repurchased   5,100,000      
PNC [Member]          
Schedule of Capitalization, Equity [Line Items]          
Common shares repurchased 2,650,857        
Common shares repurchased price per share $ 414.96        
PNC [Member] | Series C Nonvoting Participating Preferred Stock [Member]          
Schedule of Capitalization, Equity [Line Items]          
Surrender of share of series non- voting preferred stock     143,458    
PNC [Member] | Common Stock [Member]          
Schedule of Capitalization, Equity [Line Items]          
Shares issued upon conversion 823,188        
PNC [Member] | Secondary Public Offering [Member] | Common Stock [Member]          
Schedule of Capitalization, Equity [Line Items]          
Shares issued 31,628,573        
Shares issued, price per share $ 420        
PNC [Member] | Over Allotment Option [Member] | Common Stock [Member]          
Schedule of Capitalization, Equity [Line Items]          
Shares issued to purchase additional shares 2,875,325