Consolidated Statements of Shareholders' Equity - USD ($) shares in Thousands, $ in Millions		Total		Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock and Other		AOCI Attributable to Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Shares, Outstanding					471,000
Total shareholders' equity at Dec. 31, 2017		$ 25,154		$ 2,475	$ 550	$ 9,000	$ 17,540	$ (3,591)	[1]	$ (820)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Net Income	[2]	(10)					144			(154)	[3]
Net Income (Loss) Attributable to Parent		2,117					2,117
Other Comprehensive Income (Loss), Net of Tax		(900)								(900)
Noncontrolling Interest, Period Increase (Decrease)		(2)						(2)	[1]
Dividends, Common Stock, Cash		(603)					(603)
Dividends, Preferred Stock, Cash	[4]	(81)					(81)
Stock Redeemed or Called During Period, Value		(450)		(450)
Treasury Stock, Shares, Acquired					(17,000)
Treasury Stock, Value, Acquired, Cost Method		(1,160)						(1,160)	[1]
Stock Issued During Period, Value, Stock Options Exercised		36						36	[1]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period					1,000
Stock Issued During Period, Shares, Other					3,000
Stock Issued During Period, Value, Other		0			$ 3	(3)
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures					1,000
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures		38				4	(6)	40	[1]
Total shareholders' equity at Sep. 30, 2018		24,139		2,025	$ 553	9,001	19,111	(4,677)	[1]	(1,874)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Shares, Outstanding					465,000
Total shareholders' equity at Jun. 30, 2018		24,316		2,025	$ 552	8,980	18,616	(4,178)	[1]	(1,679)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss) Attributable to Parent		752					752
Other Comprehensive Income (Loss), Net of Tax		(195)								(195)
Noncontrolling Interest, Period Increase (Decrease)		(2)						(2)	[1]
Dividends, Common Stock, Cash		(229)					(229)
Dividends, Preferred Stock, Cash	[4]	(26)					(26)
Treasury Stock, Shares, Acquired					(7,000)
Treasury Stock, Value, Acquired, Cost Method		(500)						(500)	[1]
Stock Issued During Period, Value, Stock Options Exercised		2				(1)		3	[1]
Stock Issued During Period, Shares, Other					1,000
Stock Issued During Period, Value, Other		1			$ 1
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures		20				22	(2)
Total shareholders' equity at Sep. 30, 2018		$ 24,139		2,025	$ 553	9,001	19,111	(4,677)	[1]	(1,874)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Shares, Outstanding					459,000
Common Stock, Shares, Outstanding		446,888	[5]		447,000
Total shareholders' equity at Dec. 31, 2018		$ 24,280		2,025	$ 553	9,022	19,522	(5,422)	[6]	(1,420)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Net Income	[7]	31					31
Net Income (Loss) Attributable to Parent		1,891					1,891
Other Comprehensive Income (Loss), Net of Tax		1,271								1,271
Noncontrolling Interest, Period Increase (Decrease)		(2)						(2)	[6]
Dividends, Common Stock, Cash		(693)					(693)
Dividends, Preferred Stock, Cash	[8]	(77)					(77)
Treasury Stock, Shares, Acquired					(5,000)
Treasury Stock, Value, Acquired, Cost Method		(250)						(250)	[6]
Stock Issued During Period, Value, Stock Options Exercised		7				(7)		14	[6]
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures					2,000
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures		31				(26)	(10)	67	[6]
Total shareholders' equity at Sep. 30, 2019		26,489		2,025	$ 553	8,989	20,664	(5,593)	[6]	(149)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Shares, Outstanding					444,000
Total shareholders' equity at Jun. 30, 2019		25,862		2,025	$ 553	8,965	20,319	(5,599)	[6]	(401)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss) Attributable to Parent		623					623
Other Comprehensive Income (Loss), Net of Tax		252								252
Noncontrolling Interest, Period Increase (Decrease)		(2)						(2)	[6]
Dividends, Common Stock, Cash		(249)					(249)
Dividends, Preferred Stock, Cash	[8]	(26)					(26)
Stock Issued During Period, Value, Stock Options Exercised		2				(3)		5	[6]
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures		27				27	(3)	3	[6]
Total shareholders' equity at Sep. 30, 2019		$ 26,489		$ 2,025	$ 553	$ 8,989	$ 20,664	$ (5,593)	[6]	$ (149)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Shares, Outstanding		444,033	[5]		444,000

[1] At September 30, 2018, includes ($4,777) million for treasury stock, less than ($1) million for the compensation element of restricted stock, and $101 million for noncontrolling interest

[2] Related to the Company’s adoption of ASU 2014-09, ASU 2016-01, ASU 2017-12, and ASU 2018-02 on January 1, 2018. See Note 1, “Significant Accounting Policies,” to the Company's 2018 Annual Report on Form 10-K for additional information.

[3] Related to the Company’s early adoption of ASU 2018-02 on January 1, 2018. See Note 1, “Significant Accounting Policies,” to the Company's 2018 Annual Report on Form 10-K for additional information.

[4] For the three months ended September 30, 2018, dividends were $1,022.22 per share for both Series A and B Preferred Stock, $1,406.25 per share for Series F Preferred Stock, $1,262.50 per share for Series G Preferred Stock, and $1,281.25 per share for Series H Preferred Stock. For the nine months ended September 30, 2018, dividends were $3,044.44 per share for both Series A and B Preferred Stock, $1,468.75 per share for Series E Preferred Stock, $4,218.75 per share for Series F Preferred Stock, $3,787.50 per share for Series G Preferred Stock, and $4,285.07 per share for Series H Preferred Stock.

[5] Includes restricted shares of 4 thousand and 7 thousand at September 30, 2019 and December 31, 2018, respectively.

[6] At September 30, 2019, includes ($5,693) million for treasury stock, less than ($1) million for the compensation element of restricted stock, and $101 million for noncontrolling interest.

[7] Related to the Company’s adoption of ASU 2016-02 on January 1, 2019. See Note 1, “Significant Accounting Policies,” for additional information.

[8] For the three months ended September 30, 2019, dividends were $1,022.22 per share for both Series A and B Preferred Stock, $1,406.25 per share for Series F Preferred Stock, $1,262.50 per share for Series G Preferred Stock, and $1,281.25 per share for Series H Preferred Stock. For the nine months ended September 30, 2019, dividends were $3,044.44 per share for both Series A and B Preferred Stock, $4,218.75 per share for Series F Preferred Stock, $3,787.50 per share for Series G Preferred Stock, and $3,843.75 per share for Series H Preferred Stock.