Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Common Stock	Paid-in Capital	Retained Earnings	Treasury Common Stock	AOCI
Balance at Dec. 31, 2014		$ 1,741	$ 1,368	$ 29,653	$ (21,840)	$ (532)
Net income	$ 2,986	0	0	2,986	0	0
Dividends declared and paid ($1.40, $1.64 and $2.12 per share in 2015, 2016, and 2017)		0	0	(1,444)	0	0
Common stock issued for stock-based awards		0	(116)	0	513	0
Stock repurchases		0	0	0	(2,741)	0
Stock compensation		0	286	0	0	0
Excess tax benefit for stock compensation		0	90	0	0	0
Other comprehensive income (loss), net of taxes	0	0	0	0	0	0
Dividend equivalents paid on restricted stock units		0	0	(19)	0	0
Other		0	1	0	0	0
Balance at Dec. 31, 2015		1,741	1,629	31,176	(24,068)	(532)
Net income	3,595	0	0	3,595	0	0
Dividends declared and paid ($1.40, $1.64 and $2.12 per share in 2015, 2016, and 2017)		0	0	(1,646)	0	0
Common stock issued for stock-based awards		0	(204)	0	677	0
Stock repurchases		0	0	0	(2,132)	0
Stock compensation		0	252	0	0	0
Other comprehensive income (loss), net of taxes	6	0	0	0	0	6
Dividend equivalents paid on restricted stock units		0	0	(18)	0	0
Other		0	(3)	0	0	0
Balance at Dec. 31, 2016	10,473	1,741	1,674	33,107	(25,523)	(526)
Net income	3,682	0	0	3,682	0	0
Dividends declared and paid ($1.40, $1.64 and $2.12 per share in 2015, 2016, and 2017)		0	0	(2,104)	0	0
Common stock issued for stock-based awards		0	(138)	0	621	0
Stock repurchases		0	0	0	(2,556)	0
Stock compensation		0	242	0	0	0
Other comprehensive income (loss), net of taxes	142	0	0	0	0	142
Dividend equivalents paid on restricted stock units		0	0	(17)	0	0
Other		0	(2)	(6)	0	0
Balance at Dec. 31, 2017	$ 10,337	$ 1,741	$ 1,776	$ 34,662	$ (27,458)	$ (384)