NOTES PAYABLE AND LEASE OBLIGATIONS - Additional Information (Detail) $ in Millions, ¥ in Billions	1 Months Ended								12 Months Ended
	Dec. 31, 2023 JPY (¥)	Aug. 31, 2022 JPY (¥)	Mar. 31, 2021 USD ($)	Apr. 30, 2020 USD ($)	Apr. 30, 2019	Oct. 31, 2018 JPY (¥) series	Oct. 31, 2017 JPY (¥)	Dec. 31, 2016 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2024 JPY (¥)	Dec. 31, 2024 USD ($)	Apr. 01, 2024 USD ($)	Mar. 31, 2024 JPY (¥) series	Dec. 31, 2023 USD ($)	Sep. 30, 2022 JPY (¥) series	Apr. 30, 2021 JPY (¥) series	Mar. 31, 2020 JPY (¥) series	Dec. 31, 2019 JPY (¥) series	Apr. 01, 2019 JPY (¥)	Oct. 31, 2018 USD ($) series	Jan. 31, 2017 JPY (¥)	Sep. 30, 2016 USD ($) series	Aug. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)
Debt Instrument [Line Items]
Number of Senior Notes Issued Through a Private Placement (in series) | series															5
Number of series of senior notes issued through a U.S. public debt offering (in series) | series						3									3		4	5	4	4		3		2
Interest expense on debt | $									$ 194	$ 190	$ 217
Operating lease, cost | $									43	49	52
Operating lease, payments | $									$ 41	$ 48	$ 49
Private Placement
Debt Instrument [Line Items]
Debt instrument, principal amount															¥ 75.0
Senior notes
Debt Instrument [Line Items]
Debt instrument, principal amount						¥ 53.4									¥ 48.6		¥ 73.0	¥ 82.0	¥ 57.0	¥ 38.0				$ 700
3.60% senior notes due April 2030
Debt Instrument [Line Items]
Debt instrument, principal amount | $				$ 1,000
Debt instrument, interest rate	3.60%			3.60%								3.60%	3.60%			3.60%
Debt instrument, redemption, description				These notes are redeemable at the Parent Company's option in whole at any time or in part from time to time at a redemption price equal to the greater of: (i) the aggregate principal amount of the notes to be redeemed or (ii) the amount equal to the sum of the present values of the remaining scheduled payments for principal of and interest on the notes to be redeemed, not including any portion of the payments of interest accrued as of such redemption date, discounted to such redemption date on a semiannual basis at the yield to maturity for a U.S. Treasury security with a maturity comparable to the remaining term of the notes, plus 45 basis points, plus in each case, accrued and unpaid interest on the principal amount of the notes to be redeemed to, but excluding, such redemption date.
.300% senior notes due September 2025
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 12.4											¥ 12.4							¥ 12.4
Debt instrument, interest rate	0.30%											0.30%	0.30%			0.30%			0.30%
.550% senior notes due March 2030
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 13.3											¥ 13.3							¥ 13.3
Debt instrument, interest rate	0.55%											0.55%	0.55%			0.55%			0.55%
.750% senior notes due March 2032
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 20.7											¥ 20.7							¥ 20.7
Debt instrument, interest rate	0.75%											0.75%	0.75%			0.75%			0.75%
.830% senior notes due March 2035
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 10.6											¥ 10.6							¥ 10.6
Debt instrument, interest rate	0.83%											0.83%	0.83%			0.83%			0.83%
.500% senior notes due December 2029
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 12.6											¥ 12.6								¥ 12.6
Debt instrument, interest rate	0.50%											0.50%	0.50%			0.50%				0.50%
.843% senior notes due December 2031
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 9.3											¥ 9.3								¥ 9.3
Debt instrument, interest rate	0.843%											0.843%	0.843%			0.843%				0.843%
.934% senior notes due December 2034
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 9.8											¥ 9.8								¥ 9.8
Debt instrument, interest rate	0.934%											0.934%	0.934%			0.934%				0.934%
1.122% senior notes due December 2039
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 6.3											¥ 6.3								¥ 6.3
Debt instrument, interest rate	1.122%											1.122%	1.122%			1.122%				1.122%
.963% subordinated bonds paid April 2024
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 30.0																				¥ 30.0
Debt instrument, interest rate	0.963%													0.963%		0.963%					0.963%
Debt instrument, interest rate terms					These bonds bear interest at a fixed rate of .963% per annum and then at six-month Euro Yen LIBOR plus an applicable spread on and after the day immediately following April 18, 2024.
Debt instrument, redemption, description					The bonds will be callable on each interest payment date on and after April 18, 2024. In November 2019, ALIJ amended the bonds to change their duration from perpetual to a stated maturity date of April 16, 2049 and to remove provisions that permitted ALIJ to defer payments of interest under certain circumstances.
Debt instrument, principal amount redeemed | $														$ 30,000
4.750% senior notes due January 2049
Debt Instrument [Line Items]
Debt instrument, principal amount | $																						$ 550
Debt instrument, interest rate	4.75%					4.75%						4.75%	4.75%			4.75%						4.75%
Debt instrument, redemption, description						These notes are redeemable at the Parent Company's option in whole at any time or in part from time to time at a redemption price equal to the greater of: (i) the aggregate principal amount of the notes to be redeemed or (ii) the amount equal to the sum of the present values of the remaining scheduled payments for principal of and interest on the notes to be redeemed, not including any portion of the payments of interest accrued as of such redemption date, discounted to such redemption date on a semiannual basis at the yield to maturity for a U.S. Treasury security with a maturity comparable to the remaining term of the notes, plus 25 basis points, plus in each case, accrued and unpaid interest on the principal amount of the notes to be redeemed to, but excluding, such redemption date.
1.159% senior notes due October 2030
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 29.3					¥ 29.3						¥ 29.3
Debt instrument, interest rate	1.159%					1.159%						1.159%	1.159%			1.159%						1.159%
1.488% senior notes due October 2033
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 15.2					¥ 15.2						¥ 15.2
Debt instrument, interest rate	1.488%					1.488%						1.488%	1.488%			1.488%						1.488%
1.750% senior notes due October 2038
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 8.9					¥ 8.9						¥ 8.9
Debt instrument, interest rate	1.75%					1.75%						1.75%	1.75%			1.75%						1.75%
2.108% subordinated notes due October 2047
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 60.0						¥ 60.0					¥ 60.0
Debt instrument, interest rate	2.108%						2.108%					2.108%	2.108%			2.108%
Debt instrument, interest rate terms							The debentures bear interest at an initial rate of 2.108% per annum through October 22, 2027, or earlier redemption. Thereafter, the rate of interest of the debentures will be reset every five years to a rate of interest equal to the then-current JPY 5-year Swap Offered Rate plus 205 basis points.
Debt instrument, redemption, description							The debentures are redeemable (i) at any time, in whole but not in part, upon the occurrence of certain tax events or certain rating agency events, as specified in the indenture governing the terms of the debentures or (ii) on or after October 23, 2027, in whole or in part, at a redemption price equal to their principal amount plus accrued and unpaid interest to, but excluding, the date of redemption.
.932% senior notes due January 2027
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 60.0											¥ 60.0											¥ 60.0
Debt instrument, interest rate	0.932%											0.932%	0.932%			0.932%							0.932%
2.875% senior notes due October 2026
Debt Instrument [Line Items]
Debt instrument, principal amount | $																								$ 300
Debt instrument, interest rate	2.875%											2.875%	2.875%			2.875%								2.875%
4.00% senior noted due October 2046
Debt Instrument [Line Items]
Debt instrument, principal amount | $																								$ 400
Debt instrument, interest rate	4.00%											4.00%	4.00%			4.00%								4.00%
6.90% senior notes due December 2039
Debt Instrument [Line Items]
Debt instrument, principal amount | $																										$ 400
Debt instrument, interest rate	6.90%							6.90%				6.90%	6.90%			6.90%
Repayments of debt | $								$ 176
6.45% senior notes due August 2040
Debt Instrument [Line Items]
Debt instrument, principal amount | $																									$ 450
Debt instrument, interest rate	6.45%							6.45%				6.45%	6.45%			6.45%
Repayments of debt | $								$ 193
Senior Notes due 2039 and 2040
Debt Instrument [Line Items]
Expense on extinguishment of debt | $								$ (137)
.633% senior notes due April 2031
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 30.0											¥ 30.0						¥ 30.0
Debt instrument, interest rate	0.633%											0.633%	0.633%			0.633%		0.633%
.844% senior notes due April 2033
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 12.0											¥ 12.0						¥ 12.0
Debt instrument, interest rate	0.844%											0.844%	0.844%			0.844%		0.844%
1.039% senior notes due April 2036
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 10.0											¥ 10.0						¥ 10.0
Debt instrument, interest rate	1.039%											1.039%	1.039%			1.039%		1.039%
1.264% senior notes due April 2041
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 10.0											¥ 10.0						¥ 10.0
Debt instrument, interest rate	1.264%											1.264%	1.264%			1.264%		1.264%
1.560% senior notes due April 2051
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 20.0											¥ 20.0						¥ 20.0
Debt instrument, interest rate	1.56%											1.56%	1.56%			1.56%		1.56%
1.125% senior notes due March 2026
Debt Instrument [Line Items]
Debt instrument, principal amount | $			$ 400
Debt instrument, interest rate	1.125%		1.125%									1.125%	1.125%			1.125%
Debt instrument, redemption, description			These notes are redeemable at the Parent Company's option in whole at any time or in part from time to time at a redemption price equal to the greater of: (i) the aggregate principal amount of the notes to be redeemed or (ii) the amount equal to the sum of the present values of the remaining scheduled payments for principal of and interest on the notes to be redeemed, not including any portion of the payments of interest accrued as of such redemption date, discounted to such redemption date on a semiannual basis at the yield to maturity for a U.S. Treasury security with a maturity comparable to the remaining term of the notes, plus 10 basis points, plus in each case, accrued and unpaid interest on the principal amount of the notes to be redeemed to, but excluding, such redemption date.
1.075% senior notes due September 2029
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 33.4											¥ 33.4					¥ 33.4
Debt instrument, interest rate	1.075%											1.075%	1.075%			1.075%	1.075%
1.320% senior notes due December 2032
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 21.1											¥ 21.1					¥ 21.1
Debt instrument, interest rate	1.32%											1.32%	1.32%			1.32%	1.32%
1.594% senior notes due September 2037
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 6.5											¥ 6.5					¥ 6.5
Debt instrument, interest rate	1.594%											1.594%	1.594%			1.594%	1.594%
2.144% senior notes due September 2052
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 12.0											¥ 12.0					¥ 12.0
Debt instrument, interest rate	2.144%											2.144%	2.144%			2.144%	2.144%
1.958% subordinated bonds due December 2053
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 30.0											¥ 30.0
Debt instrument, interest rate	1.958%											1.958%	1.958%			1.958%
Debt instrument, interest rate terms	The bonds bear interest at an initial rate of 1.958% per annum until December 5, 2028. Thereafter, the rate of interest of the bonds will be reset every five years to a rate of interest equal to the then-current five-year JGB rate plus (i) 1.650% per annum on and after the day immediately following December 5, 2028 to December 5, 2033, and (ii) 2.650% per annum on and after the day immediately following December 5, 2033 to December 5, 2053.
Debt instrument, redemption, description	The bonds are redeemable, in whole but not in part, (i) at any time upon the occurrence of certain regulatory or tax events, as specified in the indenture governing the terms of the bonds or (ii) on each interest rate reset date on or after December 5, 2028.
Yen-denominated loans
Debt Instrument [Line Items]
Debt instrument, principal amount		¥ 107.0
Yen-denominated loan variable interest rate due August 2027
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 11.7	11.7										¥ 11.7
Debt instrument, interest rate	0.35%											0.84%	0.84%			0.35%
Yen-denominated loan variable interest rate due August 2029
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 25.3	25.3										¥ 25.3
Debt instrument, interest rate	0.45%											0.94%	0.94%			0.45%
Yen-denominated loan variable interest rate due August 2032
Debt Instrument [Line Items]
Debt instrument, principal amount	¥ 70.0	¥ 70.0										¥ 70.0
Debt instrument, interest rate	0.60%											1.09%	1.09%			0.60%
Notes Payable
Debt Instrument [Line Items]
Debt instrument, debt default, amount | $													$ 0			$ 0
Line of Credit
Debt Instrument [Line Items]
Debt instrument, debt default, amount | $													$ 0			$ 0
Lower Limit | Yen-denominated loan variable interest rate due August 2027
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		0.225%
Lower Limit | Yen-denominated loan variable interest rate due August 2029
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		0.325%
Lower Limit | Yen-denominated loan variable interest rate due August 2032
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		0.475%
Upper Limit | Yen-denominated loan variable interest rate due August 2027
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		0.625%
Upper Limit | Yen-denominated loan variable interest rate due August 2029
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		0.725%
Upper Limit | Yen-denominated loan variable interest rate due August 2032
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		1.025%