Securities (Gains and Losses Recognized in Income from Trading Securities) (Parenthetical) (Detail) - USD ($)		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Schedule Of Trading Securities And Other Trading Assets
Realized gains	[1]	$ 4,000,000	$ 1,000,000	$ 5,000,000	$ 3,000,000
Realized losses	[2]	2,000,000	3,000,000	6,000,000	5,000,000
Net unrealized gains (losses)	[3]	1,000,000	(1,000,000)	1,000,000
Corporate Banking Revenue and Wealth and Asset Management Revenue
Schedule Of Trading Securities And Other Trading Assets
Realized gains		4,000,000	1,000,000	5,000,000	2,000,000
Realized losses		$ (2,000,000)	$ (3,000,000)	$ (6,000,000)	$ (5,000,000)

[1] Includes realized gains of $ 4 and $ 5 for the three and six months ended June 30, 2016 , respectively, and $ 1 and $ 2 for the three and six months ended June 30, 2015 , respectively, recorded in corporate banking revenue and wealth and asset management revenue in the Condensed Consolidated Statements of Income.

[2] Includes realized losses of $ 2 and $ 6 for the three and six months ended June 30, 2016 , respectively, and $ 3 and $ 5 for the three and six months ended June 30, 2015 , respec tively, recorded in corporate banking revenue and wealth and asset management revenue in the Condensed Consolidated Statements of Income.

[3] Include s an immaterial amount of net unrealized gains and losses during both the three and six months ended June 30, 2016 and 2015 recorded in corporate banking revenue and wealth and asset management revenue in the Condensed Consolidated Statements of Income.