NOTES PAYABLE AND LEASE OBLIGATIONS - Summary of Notes Payable (Detail 2) - JPY (¥) ¥ in Billions	Sep. 30, 2025	Jun. 30, 2025	May 31, 2025	Dec. 31, 2024
1.125% senior sustainability notes due March 2026
Debt Instrument [Line Items]
Debt instrument, interest rate	1.125%			1.125%
2.875% senior notes due October 2026
Debt Instrument [Line Items]
Debt instrument, interest rate	2.875%			2.875%
3.60% senior notes due April 2030
Debt Instrument [Line Items]
Debt instrument, interest rate	3.60%			3.60%
6.90% senior notes due December 2039
Debt Instrument [Line Items]
Debt instrument, interest rate	6.90%			6.90%
6.45% senior notes due August 2040
Debt Instrument [Line Items]
Debt instrument, interest rate	6.45%			6.45%
4.00% senior notes due October 2046
Debt Instrument [Line Items]
Debt instrument, interest rate	4.00%			4.00%
4.750% senior notes due January 2049
Debt Instrument [Line Items]
Debt instrument, interest rate	4.75%			4.75%
.300% senior notes paid September 2025
Debt Instrument [Line Items]
Debt instrument, interest rate	0.30%			0.30%
Debt instrument, principal amount				¥ 12.4
.932% senior notes due January 2027
Debt Instrument [Line Items]
Debt instrument, interest rate	0.932%			0.932%
Debt instrument, principal amount	¥ 60.0			¥ 60.0
1.048% senior notes due March 2029
Debt Instrument [Line Items]
Debt instrument, interest rate	1.048%			1.048%
Debt instrument, principal amount	¥ 13.0			¥ 13.0
1.075% senior notes due September 2029
Debt Instrument [Line Items]
Debt instrument, interest rate	1.075%			1.075%
Debt instrument, principal amount	¥ 33.4			¥ 33.4
.500% senior notes due December 2029
Debt Instrument [Line Items]
Debt instrument, interest rate	0.50%			0.50%
Debt instrument, principal amount	¥ 12.6			¥ 12.6
.550% senior notes due March 2030
Debt Instrument [Line Items]
Debt instrument, interest rate	0.55%			0.55%
Debt instrument, principal amount	¥ 13.3			¥ 13.3
1.159% senior notes due October 2030
Debt Instrument [Line Items]
Debt instrument, interest rate	1.159%			1.159%
Debt instrument, principal amount	¥ 29.3			¥ 29.3
1.726% senior notes due October 2030
Debt Instrument [Line Items]
Debt instrument, interest rate	1.726%	1.726%
Debt instrument, principal amount	¥ 35.0	¥ 35.0
1.412% senior notes due March 2031
Debt Instrument [Line Items]
Debt instrument, interest rate	1.412%			1.412%
Debt instrument, principal amount	¥ 27.9			¥ 27.9
.633% senior notes due April 2031
Debt Instrument [Line Items]
Debt instrument, interest rate	0.633%			0.633%
Debt instrument, principal amount	¥ 30.0			¥ 30.0
.843% senior notes due December 2031
Debt Instrument [Line Items]
Debt instrument, interest rate	0.843%			0.843%
Debt instrument, principal amount	¥ 9.3			¥ 9.3
.750% senior notes due March 2032
Debt Instrument [Line Items]
Debt instrument, interest rate	0.75%			0.75%
Debt instrument, principal amount	¥ 20.7			¥ 20.7
1.990% senior notes due May 2032
Debt Instrument [Line Items]
Debt instrument, interest rate	1.99%		1.99%
Debt instrument, principal amount	¥ 18.2		¥ 18.2
1.320% senior notes due December 2032
Debt Instrument [Line Items]
Debt instrument, interest rate	1.32%			1.32%
Debt instrument, principal amount	¥ 21.1			¥ 21.1
2.003% senior notes due December 2032
Debt Instrument [Line Items]
Debt instrument, interest rate	2.003%	2.003%
Debt instrument, principal amount	¥ 23.4	¥ 23.4
.844% senior notes due April 2033
Debt Instrument [Line Items]
Debt instrument, interest rate	0.844%			0.844%
Debt instrument, principal amount	¥ 12.0			¥ 12.0
1.488% senior notes due October 2033
Debt Instrument [Line Items]
Debt instrument, interest rate	1.488%			1.488%
Debt instrument, principal amount	¥ 15.2			¥ 15.2
1.682% senior notes due March 2034
Debt Instrument [Line Items]
Debt instrument, interest rate	1.682%			1.682%
Debt instrument, principal amount	¥ 7.7			¥ 7.7
1.600% senior notes due March 2034
Debt Instrument [Line Items]
Debt instrument, interest rate	1.60%			1.60%
Debt instrument, principal amount	¥ 18.3			¥ 18.3
.934% senior notes due December 2034
Debt Instrument [Line Items]
Debt instrument, interest rate	0.934%			0.934%
Debt instrument, principal amount	¥ 9.8			¥ 9.8
.830% senior notes due March 2035
Debt Instrument [Line Items]
Debt instrument, interest rate	0.83%			0.83%
Debt instrument, principal amount	¥ 10.6			¥ 10.6
2.320% senior notes due May 2035
Debt Instrument [Line Items]
Debt instrument, interest rate	2.32%		2.32%
Debt instrument, principal amount	¥ 38.3		¥ 38.3
2.369% senior notes due June 2035
Debt Instrument [Line Items]
Debt instrument, interest rate	2.369%	2.369%
Debt instrument, principal amount	¥ 9.5	¥ 9.5
1.740% senior notes due March 2036
Debt Instrument [Line Items]
Debt instrument, interest rate	1.74%			1.74%
Debt instrument, principal amount	¥ 15.0			¥ 15.0
1.039% senior notes due April 2036
Debt Instrument [Line Items]
Debt instrument, interest rate	1.039%			1.039%
Debt instrument, principal amount	¥ 10.0			¥ 10.0
1.594% senior notes due September 2037
Debt Instrument [Line Items]
Debt instrument, interest rate	1.594%			1.594%
Debt instrument, principal amount	¥ 6.5			¥ 6.5
1.750% senior notes due October 2038
Debt Instrument [Line Items]
Debt instrument, interest rate	1.75%			1.75%
Debt instrument, principal amount	¥ 8.9			¥ 8.9
1.920% senior notes due March 2039
Debt Instrument [Line Items]
Debt instrument, interest rate	1.92%			1.92%
Debt instrument, principal amount	¥ 16.5			¥ 16.5
1.122% senior notes due December 2039
Debt Instrument [Line Items]
Debt instrument, interest rate	1.122%			1.122%
Debt instrument, principal amount	¥ 6.3			¥ 6.3
2.650% senior notes due May 2040
Debt Instrument [Line Items]
Debt instrument, interest rate	2.65%		2.65%
Debt instrument, principal amount	¥ 11.6		¥ 11.6
2.779% senior notes due June 2040
Debt Instrument [Line Items]
Debt instrument, interest rate	2.779%	2.779%
Debt instrument, principal amount	¥ 7.0	¥ 7.0
1.264% senior notes due April 2041
Debt Instrument [Line Items]
Debt instrument, interest rate	1.264%			1.264%
Debt instrument, principal amount	¥ 10.0			¥ 10.0
2.160% senior notes due March 2044
Debt Instrument [Line Items]
Debt instrument, interest rate	2.16%			2.16%
Debt instrument, principal amount	¥ 5.7			¥ 5.7
3.040% senior notes due May 2045
Debt Instrument [Line Items]
Debt instrument, interest rate	3.04%		3.04%
Debt instrument, principal amount	¥ 7.0		¥ 7.0
2.108% subordinated notes due October 2047
Debt Instrument [Line Items]
Debt instrument, interest rate	2.108%			2.108%
Debt instrument, principal amount	¥ 60.0			¥ 60.0
1.560% senior notes due April 2051
Debt Instrument [Line Items]
Debt instrument, interest rate	1.56%			1.56%
Debt instrument, principal amount	¥ 20.0			¥ 20.0
2.144% senior notes due September 2052
Debt Instrument [Line Items]
Debt instrument, interest rate	2.144%			2.144%
Debt instrument, principal amount	¥ 12.0			¥ 12.0
1.958% subordinated bonds due December 2053
Debt Instrument [Line Items]
Debt instrument, interest rate	1.958%			1.958%
Debt instrument, principal amount	¥ 30.0			¥ 30.0
2.400% senior notes due March 2054
Debt Instrument [Line Items]
Debt instrument, interest rate	2.40%			2.40%
Debt instrument, principal amount	¥ 19.5			¥ 19.5
Yen-denominated loan variable interest rate due August 2027
Debt Instrument [Line Items]
Debt instrument, interest rate	1.05%			0.84%
Debt instrument, principal amount	¥ 11.7			¥ 11.7
Yen-denominated loan variable interest rate due August 2029
Debt Instrument [Line Items]
Debt instrument, interest rate	1.15%			0.94%
Debt instrument, principal amount	¥ 25.3			¥ 25.3
Yen-denominated loan variable interest rate due August 2032
Debt Instrument [Line Items]
Debt instrument, interest rate	1.30%			1.09%
Debt instrument, principal amount	¥ 70.0			¥ 70.0