Consolidated Statements of Stockholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Treasury Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
Beginning Balance (in shares) at Dec. 31, 2015		471
Beginning Balance at Dec. 31, 2015	$ 13,384	$ 5	$ (1,837)	$ 13,394	$ (723)	$ 2,545
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,371					2,371
Other comprehensive income (loss)	(262)				(262)
Exercise of common stock options		6
Exercise of common stock options	1			1
Excess tax benefits from stock-based compensation	829			829
Stock-based compensation and issuance of employee benefit plan stock	2,962			2,962
Ending Balance (in shares) at Dec. 31, 2016		477
Ending Balance at Dec. 31, 2016	19,285	$ 5	(1,837)	17,186	(985)	4,916
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of a change in accounting principle	687					687
Net income	3,033					3,033
Other comprehensive income (loss)	501				501
Exercise of common stock options		7
Exercise of common stock options	1			1
Stock-based compensation and issuance of employee benefit plan stock	4,202			4,202
Ending Balance (in shares) at Dec. 31, 2017		484
Ending Balance at Dec. 31, 2017	27,709	$ 5	(1,837)	21,389	(484)	8,636
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of a change in accounting principle	912				(4)	916
Net income	10,073					10,073
Other comprehensive income (loss)	(547)				(547)
Exercise of common stock options		7
Exercise of common stock options	0			0
Stock-based compensation and issuance of employee benefit plan stock	5,402			5,402
Ending Balance (in shares) at Dec. 31, 2018		491
Ending Balance at Dec. 31, 2018	$ 43,549	$ 5	$ (1,837)	$ 26,791	$ (1,035)	$ 19,625