Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Millions	Total		Common Stock	Additional Paid-in Capital		Retained Earnings	Accumulated Other Comprehensive Income (Loss)		Noncontrolling Interests
Balance, beginning at Dec. 31, 2018	$ 16,580		$ 132	$ 8,176		$ 9,524	$ (1,324)		$ 72
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	375					383			(8)
Other comprehensive income (loss), net of tax	391						391
Compensation—restricted stock units	(21)			(19)		(2)
Other	4	[1]		0	[1]	5		[1]	(1)	[1]
Net change	749			(19)		386	391		(9)
Balance, ending at Jun. 30, 2019	17,329		132	8,157		9,910	(933)		63
Balance, beginning at Mar. 31, 2019	16,964		132	8,193		9,713	(1,141)		67
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	196	[2]				199			(3)
Other comprehensive income (loss), net of tax	208						208
Compensation—restricted stock units	(38)			(36)		(2)
Other	(1)					0			(1)
Net change	365			(36)		197	208		(4)
Balance, ending at Jun. 30, 2019	17,329		132	8,157		9,910	(933)		63
Balance, beginning at Dec. 31, 2019	16,367		132	8,222		8,788	(862)		87
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(292)					(284)			(8)
Other comprehensive income (loss), net of tax	828						828
Compensation—restricted stock units	(22)			(18)		(4)
Other	3			0		3	0		0
Net change	370			(18)		(432)	828		(8)
Balance, ending at Jun. 30, 2020	16,737		132	8,204		8,356	(34)		79
Balance, beginning at Mar. 31, 2020	16,532		132	8,239		8,339	(262)		84
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	18	[2]				22			(4)
Other comprehensive income (loss), net of tax	228						228
Compensation—restricted stock units	(40)			(36)		(4)
Other	(1)			1		(1)			(1)
Net change	205			(35)		17	228		(5)
Balance, ending at Jun. 30, 2020	16,737		$ 132	$ 8,204		8,356	$ (34)		$ 79
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ (147)					$ (147)

[1] {F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOmY0ZjBmNDBlN2ZkNTQ5NjY5OGMwYjYzNGU3ZGUyZDM5fFRleHRTZWxlY3Rpb246RUFFRUY2MzBDNDRENTk3NUE3MjQ4QTRBNzE3ODA3RUQM}

[2] As of and for the Three Months Ended June 30, 2020:(Dollars in millions) Regional Bank Global Corporate & Investment Banking - U.S. Transaction Banking MUSA Other MUFG Americas Holdings CorporationResults of operations Net interest income $500 $95 $46 $96 $50 $787Noninterest income 97 117 9 187 399 809Total revenue 597 212 55 283 449 1,596Noninterest expense 502 131 44 150 351 1,178(Reversal of) provision for credit losses 317 41 — — 3 361Income (loss) before income taxes and including noncontrolling interests (222) 4011133 9557Income tax expense (benefit) (1) (65) (5) — 34 75 39Net income (loss) including noncontrolling interests (157) 45 11 99 20 18Deduct: net (income) loss from noncontrolling interests — — — — 4 4Net income (loss) attributable to MUAH $(157) $45 $11 $99 $24 $22 Total assets, end of period $71,941 $21,735 $251 $27,881 $45,542 $167,350