Insurance Liabilities - Expected future benefits, expenses, and gross premiums (Details) - USD ($) $ in Millions	Jun. 30, 2023	Jun. 30, 2022
General Insurance
Liability for Future Policy Benefit, Activity [Line Items]
Undiscounted expected future benefits and expense	$ 3,165	$ 3,421
Undiscounted expected future gross premiums	4,383	4,494
Discounted expected future gross premiums (at current discount rate)	3,109	3,533
Individual Retirement
Liability for Future Policy Benefit, Activity [Line Items]
Undiscounted expected future benefits and expense	2,115	1,835
Undiscounted expected future gross premiums	0	0
Discounted expected future gross premiums (at current discount rate)	0	0
Group Retirement
Liability for Future Policy Benefit, Activity [Line Items]
Undiscounted expected future benefits and expense	316	328
Undiscounted expected future gross premiums	0	0
Discounted expected future gross premiums (at current discount rate)	0	0
Life Insurance
Liability for Future Policy Benefit, Activity [Line Items]
Undiscounted expected future benefits and expense	39,848	38,406
Undiscounted expected future gross premiums	29,792	28,810
Discounted expected future gross premiums (at current discount rate)	19,207	19,704
Institutional Markets
Liability for Future Policy Benefit, Activity [Line Items]
Undiscounted expected future benefits and expense	33,474	21,092
Undiscounted expected future gross premiums	0	0
Discounted expected future gross premiums (at current discount rate)	0	0
Other Operations
Liability for Future Policy Benefit, Activity [Line Items]
Undiscounted expected future benefits and expense	43,791	45,258
Undiscounted expected future gross premiums	2,179	2,346
Discounted expected future gross premiums (at current discount rate)	$ 1,435	$ 1,602