Derivatives - Additional Information (Detail) - USD ($)	9 Months Ended
	Mar. 31, 2017	Jun. 30, 2016
Derivative [Line Items]
Maximum length of time hedged in cash flow hedge	3 years
Minimum required liquidity under certain counterparty agreements	$ 1,000,000,000
Minimum liquidity for the period as defined by certain counterparty agreements	1,000,000,000
Estimated derivative net gains (losses) included in AOCI that will be reclassified into earnings within 12 months	$ 326,000,000
Senior Unsecured Obligations
Derivative [Line Items]
Debt instrument credit rating	AAA
Derivatives Sold | Foreign Exchange Contracts | Non-designated Hedge Derivatives
Derivative [Line Items]
Notional amounts	$ 6,300,000,000	$ 11,700,000,000
Derivatives Sold | Equity Contracts
Derivative [Line Items]
Notional amounts	1,800,000,000	2,200,000,000
Derivatives Sold | Equity Contracts | Designated Hedge Derivatives
Derivative [Line Items]
Notional amounts	1,200,000,000	986,000,000
Derivatives Sold | Interest Rate Contracts | Non-designated Hedge Derivatives
Derivative [Line Items]
Notional amounts	393,000,000	2,400,000,000
Derivatives Sold | Credit Contracts | Non-designated Hedge Derivatives
Derivative [Line Items]
Notional amounts	107,000,000	273,000,000
Derivatives Sold | Commodity Contracts | Non-designated Hedge Derivatives
Derivative [Line Items]
Notional amounts	170,000,000	162,000,000
Derivatives Sold | Cash flow hedging | Foreign Exchange Contracts
Derivative [Line Items]
Notional amounts	10,600,000,000	8,400,000,000
Derivatives Sold | Fair value hedging | Foreign Exchange Contracts
Derivative [Line Items]
Notional amounts	5,200,000,000	5,300,000,000
Derivatives Purchased | Foreign Exchange Contracts | Non-designated Hedge Derivatives
Derivative [Line Items]
Notional amounts	7,900,000,000	12,000,000,000
Derivatives Purchased | Equity Contracts
Derivative [Line Items]
Notional amounts	1,300,000,000	1,300,000,000
Derivatives Purchased | Equity Contracts | Designated Hedge Derivatives
Derivative [Line Items]
Notional amounts	1,100,000,000	737,000,000
Derivatives Purchased | Interest Rate Contracts | Non-designated Hedge Derivatives
Derivative [Line Items]
Notional amounts	438,000,000	328,000,000
Derivatives Purchased | Mortgage-backed securities | Non-designated Hedge Derivatives
Derivative [Line Items]
Notional amounts	568,000,000	548,000,000
Derivatives Purchased | Credit Contracts | Non-designated Hedge Derivatives
Derivative [Line Items]
Notional amounts	312,000,000	440,000,000
Derivatives Purchased | Commodity Contracts | Non-designated Hedge Derivatives
Derivative [Line Items]
Notional amounts	$ 306,000,000	$ 631,000,000