Earnings Per Share - Calculation of Earnings Per Share and the Reconciliation of Earnings Per Share to Earnings Per Diluted Share (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Earnings Per Share:
Net income available to common shareholders	$ 2,659	$ 1,323	$ 2,419
Less: Income allocated to participating securities	7	6	21
Net income allocated to common shareholders	$ 2,652	$ 1,317	$ 2,398
Average shares	702,188,552	714,729,585	710,433,611
Earnings per share (in dollars per share)	$ 3.78	$ 1.84	$ 3.38
Earnings Per Diluted Share:
Net income available to common shareholders	$ 2,659	$ 1,323	$ 2,419
Stock-based awards	0	0	0
Less: Income allocated to participating securities	7	6	21
Net income allocated to common shareholders	$ 2,652	$ 1,317	$ 2,398
Average shares, stock based awards	9,000,000	5,000,000	10,000,000
Average shares	711,197,805	719,735,415	720,065,498
Earnings per diluted share (in dollars per share)	$ 3.73	$ 1.83	$ 3.33