Risk Management Activities and Fair Value Measurements - Notional Amounts and Fair Values of Qualifying and Non-Qualifying Financial Instruments used in Hedging Transactions (Detail) (USD $) In Millions | Sep. 30, 2011 | Jun. 30, 2011 |
|---|---|---|
Derivatives in Cash Flow Hedging Relationships | ||
| Notional amount | $ 841 | $ 847 |
| Fair Value Asset (Liability) | (172) | (114) |
Derivatives in Cash Flow Hedging Relationships | Interest Rate | ||
| Notional amount | 0 | 0 |
| Fair Value Asset (Liability) | 0 | 0 |
Derivatives in Cash Flow Hedging Relationships | Foreign currency hedges | ||
| Notional amount | 831 | 831 |
| Fair Value Asset (Liability) | (174) | (118) |
Derivatives in Cash Flow Hedging Relationships | Commodities | ||
| Notional amount | 10 | 16 |
| Fair Value Asset (Liability) | 2 | 4 |
Derivatives in Fair Value Hedging Relationships | Interest Rate | ||
| Notional amount | 9,025 | 10,308 |
| Fair Value Asset (Liability) | 295 | 163 |
Derivatives in Net Investment Hedging Relationships | ||
| Notional amount | 1,413 | 1,540 |
| Fair Value Asset (Liability) | (177) | (138) |
Derivatives Not Designated as Hedging Instruments | ||
| Notional amount | 14,685 | 14,996 |
| Fair Value Asset (Liability) | (314) | 138 |
Derivatives Not Designated as Hedging Instruments | Foreign currency hedges | ||
| Notional amount | 14,652 | 14,957 |
| Fair Value Asset (Liability) | (312) | 139 |
Derivatives Not Designated as Hedging Instruments | Commodities | ||
| Notional amount | 33 | 39 |
| Fair Value Asset (Liability) | $ (2) | $ (1) |