Capital Stock - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions |
12 Months Ended | |||
|---|---|---|---|---|
Mar. 25, 2019 |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Schedule of Capitalization, Equity [Line Items] | ||||
| Common stock, par value | $ 0.01 | $ 0.01 | ||
| Preferred stock, par value | 0.01 | 0.01 | ||
| Dividends, cash per common or preferred share | $ 13.20 | $ 12.02 | $ 10.00 | |
| Aggregate dividends | $ 2,096 | $ 1,968 | $ 1,662 | |
| Common shares repurchased | 4,000,000.0 | |||
| Common shares repurchased, value | $ 1,666 | $ 1,660 | $ 1,100 | |
| Shares authorized to be repurchased | 5,900,000 | |||
| Private Transaction | ||||
| Schedule of Capitalization, Equity [Line Items] | ||||
| Common shares repurchased, value | $ 1,300 | |||
| Series C Nonvoting Participating Preferred Stock [Member] | ||||
| Schedule of Capitalization, Equity [Line Items] | ||||
| Preferred stock, par value | $ 0.01 | $ 0.01 | ||
| Series C Nonvoting Participating Preferred Stock [Member] | PNC [Member] | ||||
| Schedule of Capitalization, Equity [Line Items] | ||||
| Surrender of share of series non- voting preferred stock | 143,458 | 103,064 | ||