Earnings per Common Share (Schedule of Basic and Diluted Earnings per Common Share) (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Net income from continuing operations attributable to common stockholders	[1]	$ 3,065	$ 1,086	$ 1,721
Net income from continuing operations attributable to common stockholders	[1]	3,008	1,086	1,721
Loss from discontinued operations, net of tax	[1]	(5)	(1)	(6)
Net income attributable to common stockholders	[1]	$ 3,003	$ 1,085	$ 1,715
Basic weighted-average common shares outstanding	[1],[2]	362,583,000	375,629,000	393,234,000
Diluted weighted-average common shares outstanding	[1],[2],[3]	365,180,000	377,101,000	395,395,000
Basic earnings per common share
Net income from continuing operations (in dollars per share)	[1]	$ 8.30	$ 2.89	$ 4.38
Loss from discontinued operations, net of tax (in dollars per share)	[1]	(0.01)	0	(0.02)
Net income (in dollars per share)	[1]	8.28	2.89	4.36
Diluted earnings per common share
Net income from continuing operations (in dollars per share)	[1]	8.24	2.88	4.35
Loss from discontinued operations, net of tax (in dollars per share)	[1]	(0.01)	0	(0.02)
Net income (in dollars per share)	[1]	$ 8.22	$ 2.88	$ 4.34
Antidilutive securities excluded from computation of earnings per share, amount		0	800,000	0
Series B Preferred Stock
Class of Stock [Line Items]
Preferred stock dividends	[1]	$ (36)	$ 0	$ 0
Series C Preferred Stock
Class of Stock [Line Items]
Preferred stock dividends	[1]	$ (21)	$ 0	$ 0

[1] Figures in the table may not recalculate exactly due to rounding. Earnings per share is calculated based on unrounded numbers.

[2] Includes shares related to share-based compensation that vested but were not yet issued.

[3] During the year ended December 31, 2020, there were 0.8 million in shares underlying share-based awards excluded because their inclusion would have been antidilutive. There were no antidilutive shares during the years ended December 31, 2021, and 2019.