Shareholders' Equity (Details - Stock) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended									12 Months Ended
	Feb. 06, 2020	Jan. 22, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Mar. 31, 2018	Sep. 30, 2017	Mar. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Preferred stock, shares outstanding			403,000				403,000					403,000	403,000
Preferred stock, amount outstanding			$ 689				$ 689					$ 689	$ 689
Preferred stock dividend declared												$ 40	$ 36	$ 25
Dividends declared per common share												$ 0.56	$ 0.14	$ 0.00
Common stock dividends												$ 135	$ 36
Series A Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, dividend rate, percentage												5.875%
Preferred stock, shares outstanding			400,000									400,000
Preferred stock, liquidation preference per share			$ 1,000									$ 1,000
Preferred stock, amount outstanding			$ 394				394					$ 394	394
Dividends payable, date declared				Jul. 25, 2019		Feb. 07, 2019		Jul. 26, 2018	Feb. 08, 2018	Aug. 02, 2017	Feb. 02, 2017
Dividends payable, date of record				Aug. 30, 2019		Feb. 28, 2019		Aug. 31, 2018	Feb. 28, 2018	Aug. 31, 2017	Feb. 28, 2017
Dividends payable, date to be paid				Sep. 16, 2019		Mar. 15, 2019		Sep. 17, 2018	Mar. 15, 2018	Sep. 15, 2017	Mar. 15, 2017
Preferred stock dividend declared, per share				$ 29.38		$ 29.38		$ 29.38	$ 29.38	$ 29.38	$ 32.64
Preferred stock dividend declared				$ 12		$ 12		$ 12	$ 12	$ 12	$ 13
Series A Preferred Stock [Member] | LIBOR [Member]
Class of Stock [Line Items]
Preferred stock, basis spread on variable rate			4.435%									4.435%
Series A Preferred Stock [Member] | Subsequent Event [Member]
Dividends payable, date declared	Feb. 06, 2020
Dividends payable, date of record	Mar. 02, 2020
Dividends payable, date to be paid	Mar. 16, 2020
Preferred stock dividend declared, per share	$ 29.38
Series B Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, dividend rate, percentage												5.30%
Preferred stock, shares outstanding			3,000									3,000
Preferred stock, liquidation preference per share			$ 100,000									$ 100,000
Preferred stock, amount outstanding			$ 295				$ 295					$ 295	295
Dividends payable, date declared				Jul. 25, 2019		Feb. 07, 2019		Jul. 26, 2018
Dividends payable, date of record				Aug. 30, 2019		Feb. 28, 2019		Aug. 31, 2018
Dividends payable, date to be paid				Sep. 16, 2019		Mar. 15, 2019		Sep. 17, 2018
Preferred stock dividend declared, per share				$ 2,650.00		$ 2,650.00		$ 4,107.50
Preferred stock dividend declared				$ 8		$ 8		$ 12
Series B Preferred Stock [Member] | LIBOR [Member]
Class of Stock [Line Items]
Preferred stock, basis spread on variable rate			3.16%									3.16%
Series B Preferred Stock [Member] | Subsequent Event [Member]
Dividends payable, date declared	Feb. 06, 2020
Dividends payable, date of record	Mar. 02, 2020
Dividends payable, date to be paid	Mar. 16, 2020
Preferred stock dividend declared, per share	$ 2,650.00
Preferred stock dividend declared, per depositary share	$ 26.50
Common Stock
Dividends payable, date declared			Oct. 16, 2019	Jul. 17, 2019	Apr. 16, 2019	Jan. 23, 2019	Oct. 17, 2018
Dividends payable, date of record			Nov. 08, 2019	Aug. 19, 2019	May 13, 2019	Feb. 01, 2019	Oct. 30, 2018
Dividends payable, date to be paid			Nov. 15, 2019	Aug. 26, 2019	May 20, 2019	Feb. 15, 2019	Nov. 15, 2018
Dividends declared per common share			$ 0.14	$ 0.14	$ 0.14	$ 0.14	$ 0.14
Common stock dividends			$ 32	$ 34	$ 34	$ 35	$ 36					$ 135	$ 36
Common Stock | Subsequent Event [Member]
Dividends payable, date declared		Jan. 22, 2020
Dividends payable, date of record		Feb. 25, 2020
Dividends payable, date to be paid		Mar. 02, 2020
Dividends declared per common share		$ 0.14