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Debt (Detail) ¥ in Millions, $ in Millions	Jun. 30, 2025 USD ($)	Jun. 30, 2025 CNY (¥)	Apr. 30, 2025 USD ($)	Mar. 31, 2025 USD ($)
Group Syndicated Credit Facility
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity	$ 3,000
INA Senior Notes Due March 2025 \| Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount				$ 800
Debt Instrument, Interest Rate, Stated Percentage				3.15%
Commercial Paper Program \| Commercial Paper
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity	$ 2,000
Senior Notes [Member] \| INA CNH Term Loan Due April 2028 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount		¥ 1,800	$ 249
Debt Instrument, Interest Rate, Stated Percentage	2.85%	2.85%