Computation of Earnings per Common Share - Computation of Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Earnings Per Share [Abstract]
Net income available to common shareholders	$ 147	$ 137
Less: Dividends paid on and earnings allocated to participating securities	(2)	(2)
Earnings applicable to common stock	$ 145	$ 135
Weighted average common shares outstanding	465,138,238	463,292,906
Basic earnings per common share	$ 0.31	$ 0.29
Earnings applicable to common stock	$ 145	$ 135
Potential dilutive common shares	808,525	594,031
Total shares for diluted earnings per common share computation	465,946,763	463,886,937
Diluted earnings per common share and common share equivalents	$ 0.31	$ 0.29