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Credit and Other Debt Agreements - Summary of Corporate and Other Debt (Detail) - USD ($) $ in Millions | Jun. 30, 2025 | Dec. 31, 2024
--- | --- | ---
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 13,030.2 | $ 13,298.2
Less unamortized debt acquisition costs on Senior Notes and Note Purchase Agreements | (85.5) | (90.1)
Less unamortized discount on Bonds Payable | (49.6) | (51.0)
Net corporate and other debt | 12,895.1 | 13,157.1
Periodic payments of interest and principal, expires April 3, 2030 |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | 0.0 | 0.0
Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | 3,323.0 | 3,523.0
Senior Notes: |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | 9,550.0 | 9,550.0
Semi-annual payments of interest, fixed rate of 4.60%, balloon due December 15, 2027 | Senior Notes: |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 750.0 | $ 750.0
Interest rate | 4.60% | 4.60%
Semi-annual payments of interest, fixed rate of 4.85%, balloon due December 15, 2029 | Senior Notes: |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 750.0 | $ 750.0
Interest rate | 4.85% | 4.85%
Semi-annual payments of interest, fixed rate of 2.40%, balloon due November 9, 2031 | Senior Notes: |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 400.0 | $ 400.0
Interest rate | 2.40% | 2.40%
Semi-annual payments of interest, fixed rate of 5.00%, balloon due February 15, 2032 | Senior Notes: |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 500.0 | $ 500.0
Interest rate | 5.00% | 5.00%
Semi-annual payments of interest, fixed rate of 5.50%, balloon due March 2, 2033 | Senior Notes: |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 350.0 | $ 350.0
Interest rate | 5.50% | 5.50%
Semi-annual payments of interest, fixed rate of 6.50%, balloon due February 15, 2034 | Senior Notes: |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 400.0 | $ 400.0
Interest rate | 6.50% | 6.50%
Semi-annual payments of interest, fixed rate of 5.45%, balloon due July 15, 2034 | Senior Notes: |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 500.0 | $ 500.0
Interest rate | 5.45% | 5.45%
Semi-annual payments of interest, fixed rate of 5.15%, balloon due February 15, 2035 | Senior Notes: |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 1,500.0 | $ 1,500.0
Interest rate | 5.15% | 5.15%
Semi-annual payments of interest, fixed rate of 3.50%, balloon due May 20, 2051 | Senior Notes: |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 850.0 | $ 850.0
Interest rate | 3.50% | 3.50%
Semi-annual payments of interest, fixed rate of 3.05%, balloon due March 9, 2052 | Senior Notes: |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 350.0 | $ 350.0
Interest rate | 3.05% | 3.05%
Semi-annual payments of interest, fixed rate of 5.75%, balloon due March 2, 2053 | Senior Notes: |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 600.0 | $ 600.0
Interest rate | 5.75% | 5.75%
Semi-annual payments of interest, fixed rate of 6.75%, balloon due February 15, 2054 | Senior Notes: |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 600.0 | $ 600.0
Interest rate | 6.75% | 6.75%
Semi-annual payments of interest, fixed rate of 5.75%, balloon due July 15, 2054 | Senior Notes: |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 500.0 | $ 500.0
Interest rate | 5.75% | 5.75%
Semi-annual payments of interest, fixed rate of 5.55%, balloon due February 15, 2055 | Senior Notes: |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 1,500.0 | $ 1,500.0
Interest rate | 5.55% | 5.55%
Semi-annual payments of interest, fixed rate of 4.31%, balloon due June 24, 2025 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 0.0 | $ 200.0
Interest rate | 4.31% | 4.31%
Semi-annual payments of interest, fixed rate of 4.85%, balloon due February 13, 2026 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 140.0 | $ 140.0
Interest rate | 4.85% | 4.85%
Semi-annual payments of interest, fixed rate of 4.73%, balloon due February 27, 2026 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 175.0 | $ 175.0
Interest rate | 4.73% | 4.73%
Semi-annual payments of interest, fixed rate of 4.40%, balloon due June 2, 2026 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 175.0 | $ 175.0
Interest rate | 4.40% | 4.40%
Semi-annual payments of interest, fixed rate of 4.36%, balloon due June 24, 2026 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 150.0 | $ 150.0
Interest rate | 4.36% | 4.36%
Semi-annual payments of interest, fixed rate of 3.75%, balloon due January 30, 2027 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 30.0 | $ 30.0
Interest rate | 3.75% | 3.75%
Semi-annual payments of interest, fixed rate of 4.09%, balloon due June 27, 2027 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 125.0 | $ 125.0
Interest rate | 4.09% | 4.09%
Semi-annual payments of interest, fixed rate of 4.09%, balloon due August 2, 2027 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 125.0 | $ 125.0
Interest rate | 4.09% | 4.09%
Semi-annual payments of interest, fixed rate of 4.14%, balloon due August 4, 2027 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 98.0 | $ 98.0
Interest rate | 4.14% | 4.14%
Semi-annual payments of interest, fixed rate of 3.46%, balloon due December 1, 2027 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 100.0 | $ 100.0
Interest rate | 3.46% | 3.46%
Semi-annual payments of interest, fixed rate of 4.55%, balloon due June 2, 2028 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 75.0 | $ 75.0
Interest rate | 4.55% | 4.55%
Semi-annual payments of interest, fixed rate of 4.34%, balloon due June 13, 2028 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 125.0 | $ 125.0
Interest rate | 4.34% | 4.34%
Semi-annual payments of interest, fixed rate of 5.04%, balloon due February 13, 2029 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 100.0 | $ 100.0
Interest rate | 5.04% | 5.04%
Semi-annual payments of interest, fixed rate of 4.98%, balloon due February 27, 2029 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 100.0 | $ 100.0
Interest rate | 4.98% | 4.98%
Semi-annual payments of interest, fixed rate of 4.19%, balloon due June 27, 2029 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 50.0 | $ 50.0
Interest rate | 4.19% | 4.19%
Semi-annual payments of interest, fixed rate of 4.19%, balloon due August 2, 2029 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 50.0 | $ 50.0
Interest rate | 4.19% | 4.19%
Semi-annual payments of interest, fixed rate of 3.48%, balloon due December 2, 2029 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 50.0 | $ 50.0
Interest rate | 3.48% | 3.48%
Semi-annual payments of interest, fixed rate of 3.99%, balloon due January 30, 2030 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 341.0 | $ 341.0
Interest rate | 3.99% | 3.99%
Semi-annual payments of interest, fixed rate of 4.44%, balloon due June 13, 2030 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 125.0 | $ 125.0
Interest rate | 4.44% | 4.44%
Semi-annual payments of interest, fixed rate of 5.14%, balloon due March 13, 2031 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 180.0 | $ 180.0
Interest rate | 5.14% | 5.14%
Semi-annual payments of interest, fixed rate of 4.70%, balloon due June 2, 2031 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 25.0 | $ 25.0
Interest rate | 4.70% | 4.70%
Semi-annual payments of interest, fixed rate of 4.09%, balloon due January 30, 2032 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 69.0 | $ 69.0
Interest rate | 4.09% | 4.09%
Semi-annual payments of interest, fixed rate of 4.34%, balloon due June 27, 2032 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 75.0 | $ 75.0
Interest rate | 4.34% | 4.34%
Semi-annual payments of interest, fixed rate of 4.34%, balloon due August 2, 2032 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 75.0 | $ 75.0
Interest rate | 4.34% | 4.34%
Semi-annual payments of interest, fixed rate of 4.59%, balloon due June 13, 2033 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 125.0 | $ 125.0
Interest rate | 4.59% | 4.59%
Semi-annual payments of interest, fixed rate of 5.29%, balloon due March 13, 2034 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 40.0 | $ 40.0
Interest rate | 5.29% | 5.29%
Semi-annual payments of interest, fixed rate of 4.48%, balloon due June 12, 2034 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 175.0 | $ 175.0
Interest rate | 4.48% | 4.48%
Semi-annual payments of interest, fixed rate of 4.24%, balloon due January 30, 2035 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 79.0 | $ 79.0
Interest rate | 4.24% | 4.24%
Semi-annual payments of interest, fixed rate of 2.44%, balloon due February 10, 2036 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 100.0 | $ 100.0
Interest rate | 2.44% | 2.44%
Semi-annual payments of interest, fixed rate of 2.46%, balloon due May 5, 2036 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 75.0 | $ 75.0
Interest rate | 2.46% | 2.46%
Semi-annual payments of interest, fixed rate of 4.69%, balloon due June 13, 2038 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 75.0 | $ 75.0
Interest rate | 4.69% | 4.69%
Semi-annual payments of interest, fixed rate of 5.45%, balloon due March 13, 2039 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 40.0 | $ 40.0
Interest rate | 5.45% | 5.45%
Semi-annual payments of interest, fixed rate of 4.49%, balloon due January 30, 2040 | Note Purchase Agreements |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 56.0 | $ 56.0
Interest rate | 4.49% | 4.49%
Premium Financing Debt Facility - expires October 31, 2026: | Premium Financing Debt Facility |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 157.2 | $ 225.2
AUD denominated tranche, interbank rates plus 1.400% | AUD Denominated Tranche | Facility B | Premium Financing Debt Facility |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 146.3 | $ 218.2
Interest rate | 1.40% | 1.40%
NZD denominated tranche, interbank rates plus 1.850% | NZD Denominated Tranche | Facility B | Premium Financing Debt Facility |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 0.0 | $ 0.0
Interest rate | 1.85% | 1.85%
AUD denominated tranche, interbank rates plus 0.830% | AUD Denominated Tranche | Facility C and D | Premium Financing Debt Facility |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 3.2 | $ 0.0
Interest rate | 0.83% | 0.83%
NZD denominated tranche, interbank rates plus 0.990% | NZD Denominated Tranche | Facility C and D | Premium Financing Debt Facility |  |
Debt Instrument [Line Items] |  |
Total corporate and other debt | $ 7.7 | $ 7.0
Interest rate | 0.99% | 0.99%

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