| Components of debt |
The following table summarizes the major components of debt at principal amounts as of each balance sheet date (in millions) and provides the maturities and interest rate ranges of each major category as of June 30, 2026: | | | | | | | | | June 30, | | December 31, | | | 2026 | | 2025 | Commercial paper program (weighted average interest rate of 3.95% as of June 30, 2026 and 4.05% as of December 31, 2025) | | $ | 1,068 | | $ | 1,090 | Senior notes, maturing through 2054, interest rates ranging from 1.15% to 7.75% (weighted average interest rate of 4.27% as of June 30, 2026 and 4.28% as of December 31, 2025) | | | 17,483 | | | 17,498 | Canadian senior notes, C$500 million, redeemed July 2026, interest rate of 2.60% | | | 352 | | | 364 | Canadian senior notes, C$700 million, maturing July 2033, interest rate of 3.944% | | | 493 | | | — | Tax-exempt bonds, maturing through 2055, fixed and variable interest rates ranging from 0.70% to 4.60% (weighted average interest rate of 3.33% as of June 30, 2026 and 3.41% as of December 31, 2025) | | | 2,827 | | | 2,827 | Financing leases and other, maturing through 2075 (weighted average interest rate of 4.90% as of June 30, 2026 and 4.83% as of December 31, 2025) | | | 1,283 | | | 1,284 | Debt issuance costs, discounts and other | | | (150) | | | (156) | | | | 23,356 | | | 22,907 | Current portion of long-term debt | | | 1,075 | | | 711 | Long-term debt, less current portion | | $ | 22,281 | | $ | 22,196 |
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