Condensed MUFG Americas Holdings Corporation Unconsolidated Financial Statements - Statements of Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income:
Total income	$ 4,345	$ 3,985	$ 3,592
Expense:
Other expense	3,438	2,823	2,713
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	679	1,156	908
Income tax benefit	151	359	279
Equity in undistributed net income (loss) of subsidiaries:
Net Income attributable to MUAH	573	816	647
MUFG Americas Holdings Corporation
Income:
Rental Income	16	0	0
Interest income on advances to subsidiaries and deposits in bank	9	0	0
Total income	25	0	0
Expense:
Interest expense	65	21	31
Other expense	20	4	4
Total interest expense	85	25	35
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	(60)	(25)	(35)
Income tax benefit	(24)	(10)	(14)
Income (loss) before equity in undistributed net income of subsidiaries	(36)	(15)	(21)
Equity in undistributed net income (loss) of subsidiaries:
Bank subsidiary	558	752	605
Nonbank subsidiaries	51	79	63
Net Income attributable to MUAH	$ 573	$ 816	$ 647