Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net Income Attributable to MUAH	$ 186	$ 247	$ 504	$ 663
Other Comprehensive Income (Loss), Net of Tax:
Net change in unrealized gains (losses) on cash flow hedges	84	(40)	106	(24)
Net change in unrealized gains (losses) on investment securities	47	(22)	66	133
Foreign currency translation adjustment	(6)	(3)	(11)	(3)
Pension and other postretirement benefit adjustments	16	7	(43)	19
Total other comprehensive income (loss)	141	(58)	204	125
Comprehensive Income (Loss) Attributable to MUAH	327	189	708	788
Comprehensive loss from noncontrolling interests	(21)	(5)	32	(14)
Total Comprehensive Income (Loss)	$ 306	$ 184	$ 676	$ 774