Non-Insurance Revenues from Contracts with Customers (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Revenue from Contract with Customer [Abstract]
Deferred non-insurance warranty revenue	$ 4,710	$ 4,714	[1]
Contract with customer, liability, revenue recognized	400	400
Deferred non-insurance warranty acquisition expense	$ 3,671	$ 3,671	[1]

[1] As of January 1, 2023, the Company adopted 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 Condensed Consolidated Financial Statements for additional information.