Computation of Earnings per Common Share - Computation of Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Earnings Per Share [Abstract]
Net income available to common shareholders	$ 163	$ 144	$ 310	$ 281
Less: Dividends paid on and earnings allocated to participating securities	(2)	(3)	(4)	(4)
Earnings applicable to common stock	$ 161	$ 141	$ 306	$ 277
Weighted average common shares outstanding	465,811,096	464,092,947	465,476,526	463,695,136
Basic earnings per common share	$ 0.34	$ 0.30	$ 0.66	$ 0.60
Earnings applicable to common stock	$ 161	$ 141	$ 306	$ 277
Potential dilutive common shares	988,976	801,591	899,249	698,385
Total shares for diluted earnings per common share computation	466,800,072	464,894,538	466,375,775	464,393,521
Diluted earnings per common share and common share equivalents	$ 0.34	$ 0.30	$ 0.66	$ 0.60