Condensed MUFG Americas Holdings Corporation Unconsolidated Financial Statements (Parent Company) - Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Assets
Cash and cash equivalents	$ 1,909	$ 2,058
Other assets	8,496	6,537
Total assets	148,144	153,070	$ 148,897
Liabilities and Stockholders' Equity
Long-term debt	11,410	13,648
Other liabilities	2,520	2,251
Total liabilities	130,758	136,477
Stockholders' equity	17,386	16,593	$ 15,812	$ 14,885
Total liabilities and stockholders' equity	148,144	153,070
MUFG Americas Holdings Corporation
Assets
Cash and cash equivalents	1,542	407
Investments in and advances to subsidiaries: Bank subsidiary	15,990	16,993
Investments in and advances to subsidiaries: Nonbank subsidiaries	3,175	1,929
Other assets	59	25
Total assets	20,766	19,354
Liabilities and Stockholders' Equity
Long-term debt	3,470	2,932
Other liabilities	63	44
Total liabilities	3,533	2,976
Stockholders' equity	17,233	16,378
Total liabilities and stockholders' equity	$ 20,766	$ 19,354