Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Common Stock	Paid-in Capital	Retained Earnings	Treasury Common Stock	AOCI
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 ($1.64, $2.12 and $2.63 per share in 2016, 2017, and 2018)		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		1,741	1,674	33,107	(25,523)	(526)
Net income	3,682	0	0	3,682	0	0
Dividends declared and paid ($1.64, $2.12 and $2.63 per share in 2016, 2017, and 2018)		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)
Net income	5,580	0	0	5,580	0	0
Dividends declared and paid ($1.64, $2.12 and $2.63 per share in 2016, 2017, and 2018)		0	0	(2,555)	0	0
Common stock issued for stock-based awards		0	(55)	0	428	0
Stock repurchases		0	0	0	(5,100)	0
Stock compensation		0	232	0	0	0
Other comprehensive income (loss), net of taxes	(59)	0	0	0	0	(59)
Dividend equivalents paid on restricted stock units		0	0	(17)	0	0
Cumulative effect of accounting changes at Dec. 31, 2018		0	0	236	0	(30)
Other		0	(3)	0	0	0
Balance at Dec. 31, 2018	$ 8,994	$ 1,741	$ 1,950	$ 37,906	$ (32,130)	$ (473)