Summary of Changes in Accumulated Other Comprehensive Income (Loss) by Component (Parenthetical) (Detail) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Mar. 31, 2018 |
Mar. 31, 2017 |
Mar. 31, 2018 |
Mar. 31, 2017 |
|
| Derivatives | ||||
| Accumulated Other Comprehensive Income (Loss) [Line Items] | ||||
| Unrealized gains (losses), tax | $ 7 | $ 3 | $ 8 | $ 7 |
| Net change related to other comprehensive income (loss), tax | 7 | 1 | 6 | (1) |
| Investments | ||||
| Accumulated Other Comprehensive Income (Loss) [Line Items] | ||||
| Unrealized gains (losses), tax | (186) | 307 | (347) | 197 |
| Net change related to other comprehensive income (loss), tax | (331) | 34 | (949) | (457) |
| Translation adjustments and other | ||||
| Accumulated Other Comprehensive Income (Loss) [Line Items] | ||||
| Net change related to other comprehensive income (loss), tax | $ 0 | $ 0 | $ (1) | $ 7 |