Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Statement of Comprehensive Income [Abstract]
Net Income Attributable to MUAH	$ 305	$ 181	$ 354	$ 318
Net income (loss)	294	175	331	307
Other Comprehensive Income (Loss), Net of Tax:
Net change in unrealized gains (losses) on cash flow hedges	61	(30)	196	22
Net change in unrealized gains (losses) on investment securities	55	(54)	146	19
Foreign currency translation adjustment	1	2	5	(5)
Pension and other postretirement benefit adjustments	9	13	19	27
Other	1	0	0	0
Total other comprehensive income (loss)	127	(69)	366	63
Comprehensive Income (Loss) Attributable to MUAH	432	112	720	381
Comprehensive loss from noncontrolling interests	(11)	(6)	(23)	(11)
Total Comprehensive Income (Loss)	$ 421	$ 106	$ 697	$ 370