Securities Available for Sale - Additional Information (Detail) (USD $) Share data in Millions, unless otherwise specified	3 Months Ended	12 Months Ended													12 Months Ended
	Sep. 30, 2008	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Equity Securities, Other [Member]		Dec. 31, 2011 Equity Securities, Other [Member]		Dec. 31, 2012 Mortgage-backed Securities, Issued by Private Enterprises [Member]	Dec. 31, 2011 Mortgage-backed Securities, Issued by Private Enterprises [Member]	Dec. 31, 2012 Asset-backed Securities [Member]	Dec. 31, 2011 Asset-backed Securities [Member]	Dec. 31, 2012 Impaired Securities Mortgage-backed Securities, Issued by Private Enterprises [Member]	Dec. 31, 2011 Impaired Securities Mortgage-backed Securities, Issued by Private Enterprises [Member]	Dec. 31, 2010 Impaired Securities Mortgage-backed Securities, Issued by Private Enterprises [Member]	Dec. 31, 2012 Equity Securities, Coca Cola
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities Pledged as Collateral		$ 10,600,000,000	$ 9,100,000,000
Securities AFS Pledged Transferee Cannot Transfer		0	0
Sold Equity Forward Agreements, Underlying Shares		59
Executed Equity Forward Agreements, Underlying Shares	60.0
Contributed Equity Forward Agreements, Underlying Shares		1
Net Gain on Sale of Certain Other Equity Securities		1,900,000,000
Noncash Contribution Expense															38,000,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions										2
Available-for-sale Securities		21,953,000,000	28,117,000,000	702,000,000	[1]	929,000,000	[1]	209,000,000	221,000,000	216,000,000	464,000,000	209,000,000	167,000,000	1,000,000
Federal Home Loan Bank Stock				$ 229,000,000		$ 342,000,000

[1] At December 31, 2012, other equity securities was comprised of the following: $229 million in FHLB of Atlanta stock, $402 million in Federal Reserve Bank stock, $69 million in mutual fund investments, and $2 million of other. At December 31, 2011, other equity securities was comprised of the following: $342 million in FHLB of Atlanta stock, $398 million in Federal Reserve Bank stock, $187 million in mutual fund investments, and $2 million of other.