Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities
Net income	$ 2,264	$ 1,015
Adjustments to reconcile net income to net cash provided by operating activities:
Net realized capital gains	(28)	(65)
Stock-based compensation	116	76
Depreciation	303	289
Other intangible amortization	54	59
(Benefit) provision for deferred income taxes	(54)	54
Changes in operating assets and liabilities, net of effect of businesses acquired and dispositions:
Receivables	358	396
Other assets	(369)	(419)
Benefits payable	396	73
Other liabilities	641	127
Unearned revenues	3,167	2,987
Other, net	114	117
Net cash provided by operating activities	6,962	4,709
Cash flows from investing activities
Acquisitions, net of cash acquired	(10)	(7)
Purchases of property and equipment	(376)	(395)
Purchases of investment securities	(4,337)	(4,533)
Maturities of investment securities	919	1,082
Proceeds from sales of investment securities	2,028	3,319
Net cash used in investing activities	(1,776)	(534)
Cash flows from financing activities
Receipts from contract deposits, net	1,931	350
Proceeds from issuance of senior notes, net	985	0
Repayment of commercial paper, net	(153)	(1)
Change in book overdraft	(41)	(118)
Common stock repurchases	(1,819)	(75)
Dividends paid	(162)	(133)
Proceeds from stock option exercises and other	61	0
Net cash provided by financing activities	802	23
Increase in cash and cash equivalents	5,988	4,198
Cash and cash equivalents at beginning of period	3,877	2,571
Cash and cash equivalents at end of period	9,865	6,769
Supplemental cash flow disclosures:
Interest payments	124	102
Income tax payments, net	$ 1,206	$ 851