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Cash Dividends - Additional Information (Detail) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Mar. 31, 2020
Sep. 30, 2021
Sep. 30, 2020
Dividends [Abstract]          
Cash dividends paid $ 0 $ 0 $ 19 $ 0 $ 19