Reconciliation of Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Level 3) (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Jun. 30, 2011
Interest Rates [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative assets	$ 55	$ 9
Derivative liabilities	1	4
Equity Contract
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative assets	214	106
Derivative liabilities	$ 30	$ 21