Condensed Consolidated Statements Of Cash Flows (Unaudited) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities
Net income	$ 1,765	$ 565
Adjustments to reconcile net income to net cash provided by operating activities:
Net realized capital gains	(28)	(39)
Stock-based compensation	83	48
Depreciation	201	190
Other intangible amortization	36	41
Provision (benefit) for deferred income taxes	2	(24)
Changes in operating assets and liabilities, net of effect of businesses acquired and dispositions:
Receivables	(1,150)	(1,392)
Other assets	(545)	(678)
Benefits payable	275	282
Other liabilities	317	1,198
Unearned revenues	3,076	(53)
Other, net	67	68
Net cash provided by operating activities	4,099	206
Cash flows from investing activities
Acquisitions, net of cash acquired	(9)	(1)
Purchases of property and equipment	(233)	(256)
Purchases of investment securities	(3,208)	(2,528)
Maturities of investment securities	649	635
Proceeds from sales of investment securities	1,723	1,853
Net cash used in investing activities	(1,078)	(297)
Cash flows from financing activities
Receipts from contract deposits, net	2,081	221
Proceeds from issuance of senior notes, net	985	0
Repayment of commercial paper, net	(102)	0
Change in book overdraft	(95)	(109)
Common stock repurchases	(1,578)	(73)
Dividends paid	(104)	(90)
Proceeds from stock option exercises and other	54	0
Net cash provided by (used in) financing activities	1,241	(51)
Increase (decrease) in cash and cash equivalents	4,262	(142)
Cash and cash equivalents at beginning of period	3,877	2,571
Cash and cash equivalents at end of period	8,139	2,429
Supplemental cash flow disclosures:
Interest payments	92	92
Income tax payments, net	$ 694	$ 536