Fair Value Measurements (Notional Amounts And Fair Values Of Interest Rate Swaps) (Details) - Recurring - USD ($)
$ in Millions |
Apr. 30, 2019 |
Jan. 31, 2019 |
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Notional amount |
$ 10,340
|
$ 10,423
|
| Inputs, Level 2 [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Fair value |
(58)
|
(16)
|
| Fair value hedging | Interest Rate Swap [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Notional amount |
4,000
|
4,000
|
| Fair value hedging | Interest Rate Swap [Member] | Inputs, Level 2 [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Fair value |
(42)
|
(78)
|
| Net investment hedging | Cross-currency swaps |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Notional amount |
2,250
|
2,250
|
| Net investment hedging | Cross-currency swaps | Inputs, Level 2 [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Fair value |
392
|
334
|
| Cash flow hedges | Cross-currency swaps |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Notional amount |
4,090
|
4,173
|
| Cash flow hedges | Cross-currency swaps | Inputs, Level 2 [Member] |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Fair value |
$ (408)
|
$ (272)
|