Consolidated Statements of Comprehensive Income - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Net Income Attributable to MUAH	[1]	$ 229	$ 62
Other Comprehensive Income (Loss), Net of Tax:
Net change in unrealized gains (losses) on cash flow hedges		(30)	132
Net change in unrealized gains (losses) on investment securities		35	90
Foreign currency translation adjustment		1	4
Pension and other postretirement benefit adjustments		7	10
Other		0	(2)
Total other comprehensive income (loss)		13	234
Comprehensive Income (Loss) Attributable to MUAH		242	296
Comprehensive loss from noncontrolling interests		(5)	(12)
Total Comprehensive Income (Loss)		$ 237	$ 284

[1] The transferred IHC entities are not measured using a "market view" perspective.