Face (par) amount of debt instrument at time of issuance.

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Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

General and significant accounting policies (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2024	May 15, 2024	Mar. 07, 2024	Dec. 31, 2023	Jul. 01, 2023
INA Senior Notes Due March 2034 [Domain] \| Senior Notes [Member]
General and significant accounting policies [Line Items]
Debt Instrument, Face Amount			$ 1,000
Debt Instrument, Interest Rate, Stated Percentage			5.00%
Make Whole Premium Additional Percent			0.15%
INA Senior Notes Due May 2024 \| Senior Notes [Member]
General and significant accounting policies [Line Items]
Debt Instrument, Face Amount		$ 700
Debt Instrument, Interest Rate, Stated Percentage		3.35%
Huatai Group
General and significant accounting policies [Line Items]
Subsidiary, Ownership Percentage, Parent	85.50%			76.50%	69.60%