Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities
Net income	$ 3,367	$ 2,707	$ 1,683
Adjustments to reconcile net income to net cash provided by operating activities:
Loss on sale of business	0	0	786
Gains on investment securities, net	(838)	(62)	(90)
Equity in net earnings	(74)	(14)	(11)
Stock compensation	181	163	137
Depreciation	528	505	444
Amortization	88	70	90
Provision for deferred income taxes	195	162	194
Changes in operating assets and liabilities, net of effect of businesses acquired and dispositions:
Receivables	(85)	(32)	(164)
Other assets	(581)	118	(484)
Benefits payable	2,139	1,142	252
Other liabilities	599	471	(676)
Unearned revenues	71	(36)	(95)
Other	49	90	107
Net cash provided by operating activities	5,639	5,284	2,173
Cash flows from investing activities
Acquisitions, net of cash acquired	(709)	0	(354)
Purchase of equity method investment in Kindred at Home	0	0	(1,095)
Cash transferred in sale of business	0	0	(805)
Purchases of property and equipment	(964)	(736)	(612)
Purchases of investment securities	(9,125)	(6,361)	(4,687)
Maturities of investment securities	4,986	1,733	972
Proceeds from sales of investment securities	2,747	4,086	3,494
Net cash used in investing activities	(3,065)	(1,278)	(3,087)
Cash flows from financing activities
Withdrawals from contract deposits, net	(939)	(623)	(640)
Proceeds from issuance of senior notes, net	1,088	987	0
Repayment of senior notes	(400)	(400)	0
Proceeds (repayments) from issuance of commercial paper, net	295		485
Proceeds (repayments) from issuance of commercial paper, net		(360)
Proceeds from term loan	1,000	0	1,000
Repayment of term loan	(1,000)	(650)	(350)
Common stock repurchases	(1,820)	(1,070)	(1,090)
Dividends paid	(323)	(291)	(265)
Change in book overdraft	95	54	30
Proceeds from stock option exercises & other	49	58	45
Net cash used in financing activities	(1,955)	(2,295)	(785)
Increase (decrease) in cash and cash equivalents	619	1,711	(1,699)
Cash and cash equivalents at beginning of period	4,054	2,343	4,042
Cash and cash equivalents at end of period	4,673	4,054	2,343
Supplemental cash flow disclosures:
Interest payments	258	212	195
Income tax payments, net	1,132	518	631
Details of businesses acquired in purchase transactions:
Fair value of assets acquired, net of cash acquired	819	28	392
Less: Fair value of liabilities assumed	(110)	(28)	(38)
Cash paid for acquired businesses, net of cash acquired	$ 709	$ 0	$ 354