Selected Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2019

Quarterly Financial Information Disclosure [Abstract]

Schedule of Selected Quarterly Financial Data

	Quarter ended
(in millions, except per share data)	March 31		June 30		September 30		December 31
2019
Total revenues	$	934	$	935	$	969	$	1,018
Insurance costs	683		704		748		792
Operating income	82		55		68		63
Net income	63		46		55		48
Basic net income per share	$	0.91	$	0.65	$	0.80	$	0.69
Diluted net income per share	$	0.89	$	0.64	$	0.78	$	0.68
2018
Total revenues	$	861	$	850	$	875	$	917
Insurance costs	641		630		647		692
Operating income	71		76		62		42
Net income	54		58		51		29
Basic net income per share	$	0.77	$	0.82	$	0.73	$	0.41
Diluted net income per share	$	0.75	$	0.80	$	0.71	$	0.40