Securities Available for Sale (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012		Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 24,298		$ 25,170
Unrealized Gains	3,061		2,989
Unrealized Losses	36		42
Fair Value	27,323		28,117
US Treasury Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	221		671
Unrealized Gains	10		23
Unrealized Losses	0		0
Fair Value	231		694
US Government Agencies Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,671		1,843
Unrealized Gains	77		89
Unrealized Losses	1		0
Fair Value	1,747		1,932
US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	406		437
Unrealized Gains	19		21
Unrealized Losses	6		4
Fair Value	419		454
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	20,251		20,480
Unrealized Gains	718		743
Unrealized Losses	2		0
Fair Value	20,967		21,223
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	237		252
Unrealized Gains	0		0
Unrealized Losses	21		31
Fair Value	216		221
Collateralized Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	43		50
Unrealized Gains	0		0
Unrealized Losses	0		0
Fair Value	43		50
Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	394		460
Unrealized Gains	13		11
Unrealized Losses	6		7
Fair Value	401		464
Corporate And Other Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	43		49
Unrealized Gains	3		2
Unrealized Losses	0		0
Fair Value	46		51
Equity Securities, Coca Cola
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	0		0
Unrealized Gains	2,220		2,099
Unrealized Losses	0		0
Fair Value	2,220		2,099
Equity Securities, Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,032	[1]	928	[1]
Unrealized Gains	1	[1]	1	[1]
Unrealized Losses	0	[1]	0	[1]
Fair Value	1,033	[1]	929	[1]
Equity Securities, Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Federal Reserve Bank Stock	$ 398		$ 398

[1] At March 31, 2012, other equity securities included the following securities at cost: $432 million in FHLB of Atlanta stock, $398 million in Federal Reserve Bank stock, and $202 million in mutual fund investments. At December 31, 2011, other equity securities included the following securities at cost: $342 million in FHLB of Atlanta stock, $398 million in Federal Reserve Bank stock, and $187 million in mutual fund investments.