Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 4,042	$ 3,877
Investment securities	9,557	7,595
Receivables, less allowance for doubtful accounts of $96 in 2017 and $118 in 2016	854	1,280
Other current assets	2,949	3,438
Total current assets	17,402	16,190
Property and equipment, net	1,584	1,505
Long-term investment securities	2,745	2,203
Goodwill	3,281	3,272
Other long-term assets	2,166	2,226
Total assets	27,178	25,396
Current liabilities:
Benefits payable	4,668	4,563
Trade accounts payable and accrued expenses	4,069	2,467
Book overdraft	141	212
Unearned revenues	378	280
Short-term borrowings	150	300
Total current liabilities	9,406	7,822
Long-term debt	4,770	3,792
Future policy benefits payable	2,923	2,834
Other long-term liabilities	237	263
Total liabilities	17,336	14,711
Commitments and contingencies (Note 16)
Stockholders’ equity:
Preferred stock, $1 par; 10,000,000 shares authorized; none issued	0	0
Common stock, $0.16 2/3 par; 300,000,000 shares authorized; 198,572,458 shares issued at December 31, 2017 and 198,495,007 shares issued at December 31, 2016	33	33
Capital in excess of par value	2,445	2,562
Retained earnings	13,670	11,454
Accumulated other comprehensive income (loss)	19	(66)
Treasury stock, at cost, 60,893,762 shares at December 31, 2017 and 49,189,811 shares at December 31, 2016	(6,325)	(3,298)
Total stockholders’ equity	9,842	10,685
Total liabilities and stockholders’ equity	$ 27,178	$ 25,396