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Schedule II - Aflac Incorporated (Parent Only) - Summary of Notes Payable (Detail 2) ¥ in Millions, $ in Millions | Dec. 31, 2023 JPY (¥) | Dec. 31, 2022 JPY (¥) | Sep. 30, 2022 JPY (¥) | Aug. 31, 2022 JPY (¥) | Apr. 30, 2021 JPY (¥) | Mar. 31, 2021 USD ($) | Dec. 31, 2020 JPY (¥) | Apr. 30, 2020 USD ($) | Mar. 31, 2020 JPY (¥) | Oct. 31, 2018 JPY (¥) | Oct. 31, 2018 USD ($) | Oct. 31, 2017 JPY (¥) | Jan. 31, 2017 JPY (¥) | Dec. 31, 2016 | Sep. 30, 2016 USD ($) | Aug. 31, 2010 USD ($) | Dec. 31, 2009 USD ($)
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1.125% senior notes due March 2026 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 1.125% | 1.125% |  |  |  | 1.125% |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | $ |  |  |  |  |  | $ 400 |  |  |  |  |  |  |  |  |  |  |
2.875% senior notes due October 2026 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 2.875% | 2.875% |  |  |  |  |  |  |  |  |  |  |  |  | 2.875% |  |
Debt instrument, principal amount | $ |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 300 |  |
3.60% senior notes due April 2030 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 3.60% | 3.60% |  |  |  |  |  | 3.60% |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | $ |  |  |  |  |  |  |  | $ 1,000 |  |  |  |  |  |  |  |  |
6.90% senior notes due December 2039 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 6.90% | 6.90% |  |  |  |  |  |  |  |  |  |  |  | 6.90% |  |  |
Debt instrument, principal amount | $ |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 400
6.45% senior notes due August 2040 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 6.45% | 6.45% |  |  |  |  |  |  |  |  |  |  |  | 6.45% |  |  |
Debt instrument, principal amount | $ |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 450 |
4.00% senior noted due October 2046 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 4.00% | 4.00% |  |  |  |  |  |  |  |  |  |  |  |  | 4.00% |  |
Debt instrument, principal amount | $ |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 400 |  |
4.750% senior notes due January 2049 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 4.75% | 4.75% |  |  |  |  |  |  |  | 4.75% | 4.75% |  |  |  |  |  |
Debt instrument, principal amount | $ |  |  |  |  |  |  |  |  |  |  | $ 550 |  |  |  |  |  |
.300% senior notes due September 2025 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.30% | 0.30% |  |  |  |  |  |  | 0.30% |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 12,400 | ¥ 12,400 |  |  |  |  |  |  | ¥ 12,400 |  |  |  |  |  |  |  |
.932% senior notes due January 2027 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.932% | 0.932% |  |  |  |  |  |  |  |  |  |  | 0.932% |  |  |  |
Debt instrument, principal amount | ¥ 60,000 | ¥ 60,000 |  |  |  |  |  |  |  |  |  |  | ¥ 60,000 |  |  |  |
.500% senior notes due December 2029 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.50% | 0.50% |  |  |  |  | 0.50% |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 12,600 | ¥ 12,600 |  |  |  |  | ¥ 12,600 |  |  |  |  |  |  |  |  |  |
.550% senior notes due March 2030 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.55% | 0.55% |  |  |  |  |  |  | 0.55% |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 13,300 | ¥ 13,300 |  |  |  |  |  |  | ¥ 13,300 |  |  |  |  |  |  |  |
1.159% senior notes due October 2030 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 1.159% | 1.159% |  |  |  |  |  |  |  | 1.159% | 1.159% |  |  |  |  |  |
Debt instrument, principal amount | ¥ 29,300 | ¥ 29,300 |  |  |  |  |  |  |  | ¥ 29,300 |  |  |  |  |  |  |
.633% senior notes due April 2031 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.633% | 0.633% |  |  | 0.633% |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 30,000 | ¥ 30,000 |  |  | ¥ 30,000 |  |  |  |  |  |  |  |  |  |  |  |
.843% senior notes due December 2031 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.843% | 0.843% |  |  |  |  | 0.843% |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 9,300 | ¥ 9,300 |  |  |  |  | ¥ 9,300 |  |  |  |  |  |  |  |  |  |
.750% senior notes due March 2032 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.75% | 0.75% |  |  |  |  |  |  | 0.75% |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 20,700 | ¥ 20,700 |  |  |  |  |  |  | ¥ 20,700 |  |  |  |  |  |  |  |
.844% senior notes due April 2033 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.844% | 0.844% |  |  | 0.844% |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 12,000 | ¥ 12,000 |  |  | ¥ 12,000 |  |  |  |  |  |  |  |  |  |  |  |
1.488% senior notes due October 2033 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 1.488% | 1.488% |  |  |  |  |  |  |  | 1.488% | 1.488% |  |  |  |  |  |
Debt instrument, principal amount | ¥ 15,200 | ¥ 15,200 |  |  |  |  |  |  |  | ¥ 15,200 |  |  |  |  |  |  |
.934% senior notes due December 2034 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.934% | 0.934% |  |  |  |  | 0.934% |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 9,800 | ¥ 9,800 |  |  |  |  | ¥ 9,800 |  |  |  |  |  |  |  |  |  |
.830% senior notes due March 2035 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.83% | 0.83% |  |  |  |  |  |  | 0.83% |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 10,600 | ¥ 10,600 |  |  |  |  |  |  | ¥ 10,600 |  |  |  |  |  |  |  |
1.039% senior notes due April 2036 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 1.039% | 1.039% |  |  | 1.039% |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 10,000 | ¥ 10,000 |  |  | ¥ 10,000 |  |  |  |  |  |  |  |  |  |  |  |
1.750% senior notes due October 2038 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 1.75% | 1.75% |  |  |  |  |  |  |  | 1.75% | 1.75% |  |  |  |  |  |
Debt instrument, principal amount | ¥ 8,900 | ¥ 8,900 |  |  |  |  |  |  |  | ¥ 8,900 |  |  |  |  |  |  |
1.122% senior notes due December 2039 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 1.122% | 1.122% |  |  |  |  | 1.122% |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 6,300 | ¥ 6,300 |  |  |  |  | ¥ 6,300 |  |  |  |  |  |  |  |  |  |
1.264% senior notes due April 2041 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 1.264% | 1.264% |  |  | 1.264% |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 10,000 | ¥ 10,000 |  |  | ¥ 10,000 |  |  |  |  |  |  |  |  |  |  |  |
2.108% subordinated notes due October 2047 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 2.108% | 2.108% |  |  |  |  |  |  |  |  |  | 2.108% |  |  |  |  |
Debt instrument, principal amount | ¥ 60,000 | ¥ 60,000 |  |  |  |  |  |  |  |  |  | ¥ 60,000 |  |  |  |  |
1.560% senior notes due April 2051 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 1.56% | 1.56% |  |  | 1.56% |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 20,000 | ¥ 20,000 |  |  | ¥ 20,000 |  |  |  |  |  |  |  |  |  |  |  |
1.075% senior notes due September 2029 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 1.075% | 1.075% | 1.075% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 33,400 | ¥ 33,400 | ¥ 33,400 |  |  |  |  |  |  |  |  |  |  |  |  |  |
1.320% senior notes due December 2032 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 1.32% | 1.32% | 1.32% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 21,100 | ¥ 21,100 | ¥ 21,100 |  |  |  |  |  |  |  |  |  |  |  |  |  |
1.594% senior notes due September 2037 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 1.594% | 1.594% | 1.594% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 6,500 | ¥ 6,500 | ¥ 6,500 |  |  |  |  |  |  |  |  |  |  |  |  |  |
2.144% senior notes due September 2052 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 2.144% | 2.144% | 2.144% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 12,000 | ¥ 12,000 | ¥ 12,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Yen-denominated loan variable interest rate due August 2027 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.35% | 0.33% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 11,700 | ¥ 11,700 |  | ¥ 11,700 |  |  |  |  |  |  |  |  |  |  |  |  |
Yen-denominated loan variable interest rate due August 2029 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.45% | 0.43% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 25,300 | ¥ 25,300 |  | 25,300 |  |  |  |  |  |  |  |  |  |  |  |  |
Yen-denominated loan variable interest rate due August 2032 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.60% | 0.58% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 70,000 | ¥ 70,000 |  | ¥ 70,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | 1.125% senior notes due March 2026 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 1.125% | 1.125% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | 2.875% senior notes due October 2026 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 2.875% | 2.875% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | 3.60% senior notes due April 2030 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 3.60% | 3.60% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | 6.90% senior notes due December 2039 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 6.90% | 6.90% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | 6.45% senior notes due August 2040 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 6.45% | 6.45% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | 4.00% senior noted due October 2046 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 4.00% | 4.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | 4.750% senior notes due January 2049 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 4.75% | 4.75% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | .300% senior notes due September 2025 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.30% | 0.30% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 12,400 | ¥ 12,400 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | .932% senior notes due January 2027 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.932% | 0.932% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 60,000 | ¥ 60,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | .500% senior notes due December 2029 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.50% | 0.50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 12,600 | ¥ 12,600 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | .550% senior notes due March 2030 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.55% | 0.55% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 13,300 | ¥ 13,300 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | 1.159% senior notes due October 2030 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 1.159% | 1.159% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 29,300 | ¥ 29,300 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | .633% senior notes due April 2031 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.633% | 0.633% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 30,000 | ¥ 30,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | .843% senior notes due December 2031 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.843% | 0.843% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 9,300 | ¥ 9,300 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | .750% senior notes due March 2032 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.75% | 0.75% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 20,700 | ¥ 20,700 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | .844% senior notes due April 2033 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.844% | 0.844% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 12,000 | ¥ 12,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | 1.488% senior notes due October 2033 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 1.488% | 1.488% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 15,200 | ¥ 15,200 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | .934% senior notes due December 2034 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.934% | 0.934% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 9,800 | ¥ 9,800 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | .830% senior notes due March 2035 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.83% | 0.83% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 10,600 | ¥ 10,600 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | 1.039% senior notes due April 2036 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 1.039% | 1.039% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 10,000 | ¥ 10,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | 1.750% senior notes due October 2038 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 1.75% | 1.75% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 8,900 | ¥ 8,900 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | 1.122% senior notes due December 2039 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 1.122% | 1.122% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 6,300 | ¥ 6,300 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | 1.264% senior notes due April 2041 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 1.264% | 1.264% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 10,000 | ¥ 10,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | 2.108% subordinated notes due October 2047 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 2.108% | 2.108% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 60,000 | ¥ 60,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | 1.560% senior notes due April 2051 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 1.56% | 1.56% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 20,000 | ¥ 20,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | 1.075% senior notes due September 2029 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 1.075% | 1.075% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 33,400 | ¥ 33,400 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | 1.320% senior notes due December 2032 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 1.32% | 1.32% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 21,100 | ¥ 21,100 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | 1.594% senior notes due September 2037 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 1.594% | 1.594% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 6,500 | ¥ 6,500 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | 2.144% senior notes due September 2052 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 2.144% | 2.144% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 12,000 | ¥ 12,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | Yen-denominated loan variable interest rate due August 2027 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.35% | 0.33% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 11,700 | ¥ 11,700 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | Yen-denominated loan variable interest rate due August 2029 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.45% | 0.43% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 25,300 | ¥ 25,300 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Parent Company | Yen-denominated loan variable interest rate due August 2032 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate | 0.60% | 0.58% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, principal amount | ¥ 70,000 | ¥ 70,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |

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