OTTI Losses on Available for Sale Securities (Detail) - USD ($) $ in Millions		Mar. 31, 2018	Dec. 31, 2017	[3]	Mar. 31, 2017
Available-for-sale Securities	[1],[2]	$ 30,934	$ 30,947
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held		$ 23			$ 22

[1] Includes securities AFS pledged as collateral where counterparties have the right to sell or repledge the collateral of $214 million and $223 million at March 31, 2018 and December 31, 2017, respectively.

[2] Text selection found with no content.

[3] Beginning January 1, 2018, the Company reclassified equity securities previously presented in Securities available for sale to Other assets on the Consolidated Balance Sheets. Reclassifications have been made to previously reported amounts for comparability. See Note 9, "Other Assets," for additional information.