Accumulated other comprehensive income (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ 561,273
Accounting Standards Update [Extensible Enumeration]	Accounting Standards Update 2023-02 [Member]
Ending Balance	$ 649,368	$ 561,273
Unrealized investment gains (losses) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	190	(187)	$ 369
Other comprehensive income	(43)	420	(991)
Reclassifications into net earnings	(30)	(43)	435
Ending Balance	117	190	(187)
Foreign currency translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(5,393)	(6,142)	(4,092)
Other comprehensive income	(1,647)	741	(2,047)
Reclassifications into net earnings	1	8	(3)
Ending Balance	(7,039)	(5,393)	(6,142)
Long duration insurance contracts [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	1,353	1,541	(4,096)
Other comprehensive income	662	(188)	5,637
Ending Balance	2,015	1,353	1,541
Defined benefit pension plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(97)	(552)	(347)
Other comprehensive income	1,222	466	(298)
Reclassifications into net earnings	23	(11)	93
Ending Balance	1,148	(97)	(552)
Other AOCI transactions [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	184	288	43
Other comprehensive income	2	(25)	283
Reclassifications into net earnings	(11)	(79)	(38)
Ending Balance	175	184	288
Accumulated other comprehensive income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(3,763)	(5,052)	(8,123)
Other comprehensive income	196	1,414	2,584
Reclassifications into net earnings	(17)	(125)	487
Ending Balance	$ (3,584)	$ (3,763)	$ (5,052)