Premiums Receivable (Tables)

3 Months Ended

Mar. 31, 2022

Credit Loss [Abstract]

Premium Receivable, Allowance for Credit Loss [Table Text Block]

Premiums Receivable and Agents' Balances
	As of March 31, 2022		As of December 31, 2021
Premiums receivable, excluding receivables for losses within a deductible and retrospectively-rated policy premiums ("loss sensitive business")	$	4,451	$	4,130
Receivables for loss sensitive business, by credit quality:
AAA	—		—
AA	128		130
A	45		52
BBB	152		133
BB	76		64
Below BB	41		41
Total receivables for loss sensitive business	442		420
Total Premiums Receivable and Agents' Balances, Gross	4,893		4,550
ACL	(106)		(105)
Total Premiums Receivable and Agents' Balances, Net of ACL	$	4,787	$	4,445

Rollforward of ACL on Premiums Receivable and Agents' Balances for the Three Months Ended
	March 31, 2022						March 31, 2021
	Premiums Receivable and Agents' Balances, Excluding Receivables for Loss Sensitive Business		Receivables for Loss Sensitive Business		Total		Premiums Receivable and Agents' Balances, Excluding Receivables for Loss Sensitive Business		Receivables for Loss Sensitive Business		Total
Beginning ACL	$	83	$	22	$	105	$	117	$	35	$	152
Current period provision (release)	13		—		13		4		1		5
Current period write-offs	(15)		—		(15)		(15)		—		(15)
Current period recoveries	3		—		3		2		—		2
Ending ACL	$	84	$	22	$	106	$	108	$	36	$	144