Summary of Significant Accounting Policies, Revenue Recognition (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)
Revenue Recognition [Abstract]
Allowance for doubtful accounts for insurance receivables	$ 33
Minimum [Member]
Revenue Recognition [Abstract]
Coverages to vehicle or consumer goods owners	1 month
Standard contract term	2 months
Service contract term	1 year
Maximum [Member]
Revenue Recognition [Abstract]
Coverages to vehicle or consumer goods owners	10 years
Standard contract term	60 months
Service contract term	20 years