Condensed UnionBanCal Corporation Unconsolidated Financial Statements (Parent Company) (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Expense:
Interest expense	$ 248	$ 214	$ 204
Total interest expense	407	370	359
Income tax expense (benefit)	195	220	308
Equity in undistributed net income (loss) of subsidiaries:
Net Income attributable to UnionBanCal Corporation (UNBC)	667	628	762
UnionBanCal Corporation
Income:
Dividends from bank subsidiary		950
Interest income on advances to subsidiaries and deposits in bank		1	1
Total income		951	1
Expense:
Interest expense	31	23	13
Other expense	4		18
Total interest expense	35	23	31
Income (loss) before income taxes and equity in undistributed net income of subsidiaries	(35)	928	(30)
Income tax expense (benefit)	(14)	(9)	(10)
Income (loss) before equity in undistributed net income of subsidiaries	(21)	937	(20)
Equity in undistributed net income (loss) of subsidiaries:
Bank subsidiary	625	(403)	783
Nonbank subsidiary	63	94	(1)
Net Income attributable to UnionBanCal Corporation (UNBC)	$ 667	$ 628	$ 762