Goodwill (Details) $ in Millions	6 Months Ended
	Jun. 30, 2024 USD ($)
Goodwill [Roll Forward]
Balance at beginning of period	$ 19,686
Measurement-period adjustments	65
Foreign exchange revaluation and other	(174)
Balance at end of period	19,833	[1]
goodwill attributable to noncontrolling interests	500
North America Commercial P&C Insurance [Member]
Goodwill [Roll Forward]
Balance at beginning of period	6,946
Measurement-period adjustments	0
Foreign exchange revaluation and other	(10)
Balance at end of period	7,192	[1]
North American Personal P&C Insurance [Member]
Goodwill [Roll Forward]
Balance at beginning of period	2,231
Measurement-period adjustments	0
Foreign exchange revaluation and other	(4)
Balance at end of period	2,227	[1]
North America Agricultural Insurance [Member]
Goodwill [Roll Forward]
Balance at beginning of period	134
Measurement-period adjustments	0
Foreign exchange revaluation and other	0
Balance at end of period	134	[1]
Overseas General Insurance [Member]
Goodwill [Roll Forward]
Balance at beginning of period	5,262
Measurement-period adjustments	0
Foreign exchange revaluation and other	(90)
Balance at end of period	5,172	[1]
Global Reinsurance [Member]
Goodwill [Roll Forward]
Balance at beginning of period	371
Measurement-period adjustments	0
Foreign exchange revaluation and other	0
Balance at end of period	371	[1]
Segment Life [Member]
Goodwill [Roll Forward]
Balance at beginning of period	4,742
Measurement-period adjustments	65
Foreign exchange revaluation and other	(70)
Balance at end of period	4,737	[1]
healthy paws
Goodwill [Roll Forward]
Acquisition of Healthy Paws	256
healthy paws | North America Commercial P&C Insurance [Member]
Goodwill [Roll Forward]
Acquisition of Healthy Paws	256
healthy paws | North American Personal P&C Insurance [Member]
Goodwill [Roll Forward]
Acquisition of Healthy Paws	0
healthy paws | North America Agricultural Insurance [Member]
Goodwill [Roll Forward]
Acquisition of Healthy Paws	0
healthy paws | Overseas General Insurance [Member]
Goodwill [Roll Forward]
Acquisition of Healthy Paws	0
healthy paws | Global Reinsurance [Member]
Goodwill [Roll Forward]
Acquisition of Healthy Paws	0
healthy paws | Segment Life [Member]
Goodwill [Roll Forward]
Acquisition of Healthy Paws	$ 0

[1] Includes $500 million attributable to noncontrolling interests.