Derivative Instruments - Asset and Liability Management Derivative Positions of Company (Parenthetical) (Detail) - Asset and Liability Management Positions [Member] - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Derivative [Line Items]
Notional Value, Assets	$ 36,747	$ 25,635
Notional Value, Liabilities	46,687	26,756
Fair Value, Liabilities	229	123
Swap [Member] | Visa Class B Shares [Member]
Derivative [Line Items]
Notional Value, Liabilities	1,600	1,500
Fair Value, Liabilities	$ 64	$ 84
Derivative Liability Average Remaining Maturity Period	1 year 3 days	1 year 6 months
Underwriting Purchase and Sale Commitments [Member]
Derivative [Line Items]
Notional Value, Assets	$ 825	$ 1
Notional Value, Liabilities	$ 825	$ 1