Premiums Receivable (Tables)

12 Months Ended

Dec. 31, 2021

Credit Loss [Abstract]

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

Premiums Receivable and Agents' Balances
	As of December 31,
	2021		2020
Premiums receivable, excluding receivables for losses within a deductible and retrospectively-rated policy premiums ("loss sensitive business")	$	4,130	$	3,851
Receivables for loss sensitive business, by credit quality:
AAA	—		—
AA	130		142
A	52		62
BBB	133		185
BB	64		115
Below BB	41		65
Total receivables for loss sensitive business	420		569
Total Premiums Receivable and Agents' Balances, Gross	4,550		4,420
ACL	(105)		(152)
Total Premiums Receivable and Agents' Balances, Net of ACL	$	4,445	$	4,268

Rollforward of ACL on Premiums Receivable and Agents' Balances for the Year Ended
	December 31, 2021						December 31, 2020
	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	$	117	$	35	$	152	$	85	$	60	$	145
Cumulative effect of accounting change [1]							(2)		(21)		(23)
Adjusted beginning ACL	117		35		152		83		39		122
Current period provision (release)	17		(13)		4		78		(4)		74
Current period gross write-offs	(59)		—		(59)		(49)		—		(49)
Current period gross recoveries	8		—		8		5		—		5
Ending ACL	$	83	$	22	$	105	$	117	$	35	$	152

[1]Represents the adjustment to the ACL recorded on adoption of accounting guidance for credit losses on January 1, 2020. The adjusted beginning ACL was based on the Company's historical loss information adjusted for current conditions and the forecasted economic environment at the time the guidance was adopted. For further information refer to Note 1 - Basis of Presentation and Significant Accounting Policies