Condensed Consolidated Statements Of Equity - USD ($) $ in Millions	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Noncontrolling Interests [Member]	Noncontrolling Interests [Member] Preferred Stock [Member]
Balance at beginning of period at Dec. 31, 2017	$ 36,200		$ 14	$ 25,371	$ 17,627	$ (8,011)	$ 1,199
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of accounting standards	(1,144)				(1,046)	(98)
Net income	1,040				1,046		(6)
Other comprehensive income (loss)	27					28	(1)
Purchase of common stock	(100)			(44)	(56)
Cash dividends paid on common stock	(536)				(536)
Dividends to noncontrolling interests	(30)						(30)
Other	1			10	(7)		(2)
Balance at end of period at Mar. 31, 2018	35,458		14	25,337	17,028	(8,081)	1,160
Balance at beginning of period at Dec. 31, 2017	36,200		14	25,371	17,627	(8,011)	1,199
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	3,406
Other comprehensive income (loss)	(67)
Balance at end of period at Jun. 30, 2018	38,636		14	25,465	18,873	(8,171)	2,455
Balance at beginning of period at Mar. 31, 2018	35,458		14	25,337	17,028	(8,081)	1,160
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,366				2,390		(24)
Other comprehensive income (loss)	(94)					(90)	(4)
Issuance of preferred stock (Note 16)		$ 1,261						$ 1,261
Cash dividends paid on common stock	(535)				(535)
Dividends to noncontrolling interests	(7)						(7)
Other	187			128	(10)		69
Balance at end of period at Jun. 30, 2018	38,636		14	25,465	18,873	(8,171)	2,455
Balance at beginning of period at Dec. 31, 2018	42,777		14	25,563	22,322	(9,039)	3,917
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,145				2,157		(12)
Other comprehensive income (loss)	185					190	(5)
Stock based compensation	89			95	(6)
Cash dividends paid on common stock	(539)				(539)
Dividends to noncontrolling interests	(18)						(18)
Other	(1)			3	5		(9)
Balance at end of period at Mar. 31, 2019	44,638		14	25,661	23,939	(8,849)	3,873
Balance at beginning of period at Dec. 31, 2018	42,777		14	25,563	22,322	(9,039)	3,917
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	4,548
Other comprehensive income (loss)	259
Balance at end of period at Jun. 30, 2019	47,089		14	25,765	25,807	(8,770)	4,273
Balance at beginning of period at Mar. 31, 2019	44,638		14	25,661	23,939	(8,849)	3,873
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,403				2,418		(15)
Other comprehensive income (loss)	74					79	(5)
Issuance of preferred stock (Note 16)		$ 408						$ 408
Stock based compensation	69			78	(9)
Cash dividends paid on common stock	(540)				(540)
Dividends to noncontrolling interests	(23)						(23)
Other	60			26	(1)		35
Balance at end of period at Jun. 30, 2019	$ 47,089		$ 14	$ 25,765	$ 25,807	$ (8,770)	$ 4,273