Earnings Per Common Share - Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net earnings to common	$ 3,233	$ 1,793	$ 4,553	$ 6,173
Weighted average basic shares	355.9	370.0	356.5	374.7
Effect of dilutive:
RSUs	4.0	4.3	3.5	3.5
Weighted average diluted shares	359.9	374.3	360.0	378.2
Basic EPS	$ 9.07	$ 4.83	$ 12.71	$ 16.43
Diluted EPS	$ 8.98	$ 4.79	$ 12.65	$ 16.32