Exit and Implementation Costs (Movement in Exit and Implementation Costs) (Details) - Initiative [Member] - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | 12 Months Ended |
|---|---|---|---|
Mar. 31, 2025 |
Mar. 31, 2025 |
Dec. 31, 2024 |
|
| Restructuring Reserve [Roll Forward] | |||
| Restructuring reserve, beginning of period | $ 57 | $ 0 | |
| Charges | 15 | 68 | |
| Cash paid | (18) | $ (29) | (11) |
| Restructuring reserve, end of period | 54 | 54 | 57 |
| Exit Costs [Member] | |||
| Restructuring Reserve [Roll Forward] | |||
| Restructuring reserve, beginning of period | 35 | 0 | |
| Charges | 0 | 35 | |
| Cash paid | (1) | (1) | 0 |
| Restructuring reserve, end of period | 34 | 34 | 35 |
| Implementation Costs [Member] | |||
| Restructuring Reserve [Roll Forward] | |||
| Restructuring reserve, beginning of period | 22 | 0 | |
| Charges | 15 | 33 | |
| Cash paid | (17) | (28) | (11) |
| Restructuring reserve, end of period | $ 20 | $ 20 | $ 22 |