Future policy benefits (Premiums & interest) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums or Assessments	$ 4,846	$ 3,015	$ 1,843
Interest Accretion	332	228	168
Term Life Insurance | Life Insurance [Member]
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums or Assessments	641	472	375
Interest Accretion	19	12	8
Whole Life Insurance | Life Insurance [Member]
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums or Assessments	1,259	651	390
Interest Accretion	165	121	101
Accident and Health [Member] | Life Insurance [Member]
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums or Assessments	2,918	1,875	1,068
Interest Accretion	141	92	57
Insurance, Other [Member] | Life Insurance [Member]
Liability for Future Policy Benefit, Activity [Line Items]
Gross Premiums or Assessments	28	17	10
Interest Accretion	$ 7	$ 3	$ 2