Reclassification Out of Accumulated Other Comprehensive Income (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Reclassifications Out Of Accumulated Other Comprehensive Income
Net periodic pension cost	$ 13		$ 17	$ 14
Income Before Income Taxes	2,598		2,210	1,831
Applicable income tax expense	772		636	533
Net income	1,836		1,576	1,297
Net unrealized gains on available-for-sale securities | Net losses included in net income
Reclassifications Out Of Accumulated Other Comprehensive Income
Reclassification adjustment for net losses (gains) included in net income	(6)	[1]
Income Before Income Taxes	(6)	[1]
Applicable income tax expense	2	[1]
Net income	(4)	[1]
Net unrealized gains on cash flow hedge derivatives
Reclassifications Out Of Accumulated Other Comprehensive Income
Income Before Income Taxes	44	[1]
Applicable income tax expense	(15)	[1]
Net income	29	[1]
Net unrealized gains on cash flow hedge derivatives | Interest rate contracts related to C&I loans
Reclassifications Out Of Accumulated Other Comprehensive Income
Reclassification adjustment for net gains on cash flow hedge derivatives included in net income	45	[1]
Net unrealized gains on cash flow hedge derivatives | Interest rate contracts related to long-term debt
Reclassifications Out Of Accumulated Other Comprehensive Income
Reclassification adjustment for net gains on cash flow hedge derivatives included in net income	(1)	[1]
Amortization of defined periodic benefit costs | Amortization of net actuarial (loss) gain
Reclassifications Out Of Accumulated Other Comprehensive Income
Net periodic pension cost	(11)	[1],[2]
Income Before Income Taxes	(16)	[1]
Applicable income tax expense	6	[1]
Net income	(10)	[1]
Amortization of defined periodic benefit costs | Settlements
Reclassifications Out Of Accumulated Other Comprehensive Income
Net periodic pension cost	(5)	[1],[2]
Total reclassifications for the period
Reclassifications Out Of Accumulated Other Comprehensive Income
Net income	$ 15	[1]

[1] Amounts in parentheses indicate reductions to net income.

[2] This AOCI component is included in the computation of net periodic benefit cost. Refer to Note 21 for information on the computation of net periodic benefit cost.