Non-Insurance Revenues from Contracts with Customers (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022		Dec. 31, 2021
Revenue from External Customer [Line Items]
Deferred non-insurance warranty revenue	$ 4,694	$ 4,714	[1]	$ 4,503
Contract with customer, liability, revenue recognized	1,400	1,300
Deferred non-insurance warranty acquisition expense	3,661	3,671	[1]	$ 3,476
Amortization of deferred sales commissions	1,200
Capitalized Commission Costs
Revenue from External Customer [Line Items]
Deferred non-insurance warranty acquisition expense	3,600
Capitalized Administrator Service Costs
Revenue from External Customer [Line Items]
Deferred non-insurance warranty acquisition expense	$ 62	$ 53

[1] As of January 1, 2023, the Company adopted ASU 2018-12, Financial Services-Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts (ASU 2018-12) using the modified retrospective method applied as of the transition date of January 1, 2021. Prior period amounts in the financial statements have been adjusted to reflect application of the new guidance. See Note A to the Consolidated Financial Statements for additional information.