Components of Net Periodic Benefit Cost (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011	Sep. 30, 2012		Sep. 30, 2011
Pension Plans, Defined Benefit
Service cost	$ 0		$ 18	$ 0		$ 53
Interest cost	30		32	90		97
Expected return on plan assets	(43)		(47)	(129)		(142)
Amortization of prior service cost	0		(5)	0		(14)
Recognized net actuarial loss	6		11	18		32
Defined Benefit Plan, Settlements, Benefit Obligation	2	[1]	0	2	[1]	0
Net periodic benefit cost	(5)		9	(19)		26
Other Postretirement Benefit Plans, Defined Benefit
Service cost	0		0	0		0
Interest cost	2		3	5		7
Expected return on plan assets	(2)		(2)	(5)		(6)
Amortization of prior service cost	0		0	0		0
Recognized net actuarial loss	0		0	0		1
Defined Benefit Plan, Settlements, Benefit Obligation	0		0	0		0
Net periodic benefit cost	$ 0		$ 1	$ 0		$ 2

[1] Interim remeasurement was required on September 15, 2012 for the SunTrust SERP to reflect settlement accounting.