Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash flows from operating activities
Net income	$ 828	$ 473
Adjustments to reconcile net income to net cash (used in) provided by operating activities:
Gains on investment securities, net	(10)	(49)
Equity in net earnings	(21)	(8)
Stock-based compensation	39	36
Depreciation	153	124
Amortization	15	21
Benefit for deferred income taxes	0	(3)
Changes in operating assets and liabilities, net of effect of businesses acquired and dispositions:
Receivables	(1,049)	(953)
Other assets	(1,095)	(1,470)
Benefits payable	466	1,086
Other liabilities	(151)	1,203
Unearned revenues	7	27
Other	(19)	(13)
Net cash (used in) provided by operating activities	(837)	474
Cash flows from investing activities
Acquisitions, net of cash acquired	(123)	(709)
Purchases of property and equipment	(290)	(192)
Purchases of investment securities	(3,720)	(2,459)
Maturities of investment securities	692	735
Proceeds from sales of investment securities	1,953	1,415
Net cash used in investing activities	(1,488)	(1,210)
Cash flows from financing activities
Receipts from contract deposits, net	1,015	574
Proceeds from issuance of senior notes, net	0	1,090
Proceeds from issuance of commercial paper, net	603	198
Proceeds from term loan	0	1,000
Change in book overdraft	23	(55)
Common stock repurchases	(30)	(17)
Dividends paid	(83)	(73)
Proceeds from stock option exercises and other, net	1	19
Net cash provided by financing activities	1,529	2,736
(Decrease) increase in cash and cash equivalents	(796)	2,000
Cash and cash equivalents at beginning of period	4,673	4,054
Cash and cash equivalents at end of period	3,877	6,054
Supplemental cash flow disclosures:
Interest payments	40	40
Income tax payments, net	$ (1)	$ (6)