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Credit and Other Debt Agreements - Summary of Corporate and Other Debt (Detail) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022
--- | --- | ---
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | $ 8,032.0 | $ 6,499.9
Less unamortized debt acquisition costs on Senior Notes and Note Purchase Agreements | (38.4) | (20.6)
Less unamortized discount on Bonds Payable | (28.6) | (14.6)
Semi-annual payments of interest, Net | 7,965.0 | 6,464.7
Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 3,948.0 | 4,248.0
Unsecured Senior Notes [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 3,550.0 | 1,950.0
Fixed Rate of 2.40%, Balloon Due November 9, 2031 [Member] | Unsecured Senior Notes [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 400.0 | 400.0
Fixed Rate of 5.50%, Balloon Due March 2, 2033 [Member] | Unsecured Senior Notes [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 350.0 |
Fixed Rate of 3.50%, Balloon Due May 20, 2051 [Member] | Unsecured Senior Notes [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 850.0 | 850.0
Fixed Rate of 3.05%, Balloon Due March 9, 2052 [Member] | Unsecured Senior Notes [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 350.0 |
Fixed Rate of 5.75%, Balloon Due March 2, 2053 [Member] | Unsecured Senior Notes [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 600.0 | 350.0
Fixed Rate of 6.50%, Balloon due February 15, 2034 [Member] | Unsecured Senior Notes [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 400.0 | 350.0
Fixed Rate of 6.75%, Balloon Due February 15, 2054 [Member] | Unsecured Senior Notes [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 600.0 |
Fixed Rate of 5.49%, Balloon Due February 10, 2023 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest |  | 50.0
Fixed Rate of 4.13%, Balloon Due June 24, 2023 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest |  | 200.0
Fixed Rate of 4.72%, Balloon due February 13, 2024 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 100.0 | 100.0
Fixed Rate of 4.58%, Balloon Due February 27, 2024 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 325.0 | 325.0
Floating Interest Rate of 1.40% LIBOR Plus Balloon Due June 13, 2024 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest |  | 50.0
Fixed Rate of 4.31%, Balloon Due June 24, 2025 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 200.0 | 200.0
Fixed Rate of 4.85%, Balloon due February 13, 2026 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 140.0 | 140.0
Fixed Rate of 4.73%, Balloon Due February 27, 2026 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 175.0 | 175.0
Fixed Rate of 4.40%, Balloon Due June 2, 2026 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 175.0 | 175.0
Fixed Rate of 4.36%, Balloon Due June 24, 2026 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 150.0 | 150.0
Fixed Rate of 3.75%, Balloon Due January 30, 2027 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 30.0 | 30.0
Fixed Rate of 4.09%, Balloon Due June 27, 2027 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 125.0 | 125.0
Fixed Rate of 4.09%, Balloon Due August 2, 2027 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 125.0 | 125.0
Fixed Rate of 4.14%, Balloon Due August 4, 2027 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 98.0 | 98.0
Fixed Rate of 3.46%, Balloon Due December 1, 2027 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 100.0 | 100.0
Fixed Rate of 4.55%, Balloon Due June 2, 2028 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 75.0 | 75.0
Fixed Rate of 4.34%, Balloon due June 13, 2028 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 125.0 | 125.0
Fixed Rate of 5.04%, Balloon due February 13, 2029 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 100.0 | 100.0
Fixed Rate of 4.98%, Balloon Due February 27, 2029 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 100.0 | 100.0
Fixed Rate of 4.19%, Balloon Due June 27, 2029 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 50.0 | 50.0
Fixed Rate of 4.19%, Balloon Due August 2, 2029 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 50.0 | 50.0
Fixed Rate of 3.48%, Balloon Due December 2, 2029 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 50.0 | 50.0
Fixed Rate of 3.99%, Balloon Due January 30, 2030 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 341.0 | 341.0
Fixed Rate of 4.44%, Balloon Due June 13, 2030 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 125.0 | 125.0
Fixed Rate of 5.14%, Balloon due March 13, 2031 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 180.0 | 180.0
Fixed Rate of 4.70%, Balloon Due June 2, 2031 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 25.0 | 25.0
Fixed Rate of 4.09%, Balloon Due January 30, 2032 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 69.0 | 69.0
Fixed Rate of 4.34%, Balloon Due June 27, 2032 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 75.0 | 75.0
Fixed Rate of 4.34%, Balloon Due August 2, 2032 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 75.0 | 75.0
Fixed Rate of 4.59%, Balloon due June 13, 2033 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 125.0 | 125.0
Fixed Rate of 5.29%, balloon due March 13, 2034 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 40.0 | 40.0
Fixed Rate of 4.48%, Balloon Due June 12, 2034 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 175.0 | 175.0
Fixed Rate of 4.24%, Balloon Due January 30, 2035 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 79.0 | 79.0
Fixed Rate of 2.44%, Balloon Due February 10, 2036 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 100.0 | 100.0
Fixed Rate of 2.46%, Balloon Due May 5, 2036 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 75.0 | 75.0
Fixed Rate of 4.69%, Balloon Due June 13, 2038 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 75.0 | 75.0
Fixed Rate of 5.45%, balloon due March 13, 2039 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 40.0 | 40.0
Interbank rates plus 1.500% Expires October 31, 2025 [Member] | AUD Denominated Tranche [Member] | Facility B [Member] | Premium Financing Debt Facility [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 249.0 | 217.6
Fixed Rate of 4.49%, Balloon Due January 30, 2040 [Member] | Note Purchase Agreements [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 56.0 | 56.0
Prime or SOFR Plus up to 1.075%, Expires June 22, 2028 [Member] | Unsecured Multicurrency Credit Agreement [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 245.0 | 60.0
Interbank Rates Plus 0.830% Expires October 31, 2025 [Member] | AUD Denominated Tranche [Member] | Facility C and D [Member] | Premium Financing Debt Facility [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 31.4 | 15.2
Interbank Rates Plus 0.990% Expires October 31, 2025 [Member] | NZD Denominated Tranche [Member] | Facility B [Member] | Premium Financing Debt Facility [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | 8.6 | 9.1
Interbank Rates Expires October 31, 2025 [Member] | Premium Financing Debt Facility [Member] |  |
Debt Instrument [Line Items] |  |
Semi-annual payments of interest | $ 289.0 | $ 241.9

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