SCHEDULE I - PARENT COMPANY FINANCIAL INFORMATION (Condensed Statements of Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues:
Total revenues	$ 77,155	$ 64,888	$ 56,912
Expenses:
Operating costs	10,052	7,381	7,525
Depreciation	528	505	444
Interest	283	242	218
Other expense (income), net	103	(506)	33
Loss on sale of business	0	0	786
Provision (benefit) for income taxes	1,307	763	391
Equity in net earnings	74	14	11
Net income	3,367	2,707	1,683
Parent Company
Revenues:
Management fees charged to operating subsidiaries	2,216	1,789	1,666
Investment and other income, net	763	28	30
Total revenues	2,979	1,817	1,696
Expenses:
Operating costs	2,204	1,577	1,468
Depreciation	397	387	342
Interest	283	242	218
Total operating expenses	2,884	2,206	2,028
Other expense (income), net	60	(506)	33
Loss on sale of business	0	0	782
Income (loss) before income taxes and equity in net earnings of subsidiaries	35	117	(1,147)
Provision (benefit) for income taxes	18	27	(542)
Income (loss) before equity in net earnings of subsidiaries	17	90	(605)
Equity in net earnings of subsidiaries	3,269	2,603	2,277
Equity in net earnings	81	14	11
Net income	$ 3,367	$ 2,707	$ 1,683