Preferred and Common Stock - Schedule of Activity for Stock Options and Stock Awards (Details) shares in Millions	12 Months Ended
	Dec. 31, 2020 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of awards, outstanding beginning of year (in shares) | shares	7
Number of awards, granted (in shares) | shares	6
Number of awards, exercised (in shares) | shares	0
Number of awards, converted (in shares) | shares	(4)
Number of awards, expired or forfeited (in shares) | shares	0
Number of awards, canceled (in shares) | shares	(1)
Number of awards, adjustment (in shares) | shares	1
Number of awards, performance share adjustment (in shares) | shares	0
Number of awards, outstanding end of year (in shares) | shares	9
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted average FMV per award, outstanding beginning of year (in usd per share) | $ / shares	$ 22.05
Weighted average FMV per award, granted (in usd per share) | $ / shares	10.89
Weighted average FMV per award, exercised (in usd per share) | $ / shares	0
Weighted average FMV per award, converted (in usd per share) | $ / shares	19.54
Weighted average FMV per award, expired or forfeited (in usd per share) | $ / shares	19.57
Weighted average FMV per award, canceled (in usd per share) | $ / shares	23.84
Weighted average FMV per award, adjustment (in usd per share) | $ / shares	19.10
Weighted average FMV per award, performance share adjustment (in usd per share) | $ / shares	21.20
Weighted average FMV per award, outstanding, end of year (in usd per share) | $ / shares	$ 13.68
Stock options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of options outstanding at the beginning of the year (in shares) | shares	7
Number of options granted (in shares) | shares	0
Number of options exercised (in shares) | shares	(2)
Number of options converted (in shares) | shares	0
Number of options expired or forfeited (in shares) | shares	(1)
Number of options canceled (in shares) | shares	(1)
Number of options adjustment (in shares) | shares	0
Performance share adjustment (in shares) | shares	0
Number of options outstanding at the end of the year (in shares) | shares	3
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted average exercise price, outstanding beginning of year (in usd per share) | $ / shares	$ 25.75
Weighted average exercise price, granted (in usd per share) | $ / shares	0
Weighted average exercise price, exercised (in usd per share) | $ / shares	21.65
Weighted average exercise price, converted (in usd per share) | $ / shares	0
Weighted average exercise price, expired or forfeited (in usd per share) | $ / shares	30.12
Weighted average exercise price, expired or canceled (in usd per share) | $ / shares	27.85
Weighted average exercise price, expired or adjustment (in usd per share) | $ / shares	24.35
Weighted average exercise price, performance share adjustment (in usd per share) | $ / shares	0
Weighted average exercise price, outstanding end of year (in usd per share) | $ / shares	$ 24.47