Share-Based Payments (Compensation Cost Recognized and Related Income Tax Benefit for Stock Options, Restricted Stock Shares, Restricted Stock Units, and Performance Share Awards) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total Compensation Cost Recognized	$ 254	$ 208	$ 268
Income Tax Benefit	59	48	61
Assurance IQ
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total Compensation Cost Recognized	3	12	16
Income Tax Benefit	1	3	3
Employee stock options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total Compensation Cost Recognized	0	1	2
Income Tax Benefit	0	0	0
Employee stock options | Assurance IQ
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total Compensation Cost Recognized	2	10	14
Income Tax Benefit	1	2	3
Employee restricted stock units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total Compensation Cost Recognized	200	189	178
Income Tax Benefit	47	44	41
Employee restricted stock units | Assurance IQ
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total Compensation Cost Recognized	1	2	2
Income Tax Benefit	0	1	0
Employee performance shares and performance units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total Compensation Cost Recognized	54	18	88
Income Tax Benefit	12	4	20
Employee performance shares and performance units | Assurance IQ
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total Compensation Cost Recognized	0	0	0
Income Tax Benefit	$ 0	$ 0	$ 0