Non-Insurance Revenues from Contracts with Customers (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Revenue from External Customer [Line Items]
Deferred non-insurance warranty revenue	$ 4,714	$ 4,503
Contract with customer, liability, revenue recognized	1,300	1,200
Deferred non-insurance warranty acquisition expense	3,671	3,476
Amortization of deferred sales commissions	1,200	1,100
Capitalized Commission Costs
Revenue from External Customer [Line Items]
Deferred non-insurance warranty acquisition expense	3,600	3,500
Capitalized Administrator Service Costs
Revenue from External Customer [Line Items]
Deferred non-insurance warranty acquisition expense	$ 53	$ 47