Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) shares in Millions, $ in Millions		Total	Common Stock	Additional Paid-In Capital	Retained Earnings / (Accumulated Deficit)	Accumulated Other Comprehensive Loss	Treasury Stock
Beginning balance at Dec. 31, 2019		$ 15,358	$ 0	$ 11,129	$ 12,454	$ (7,989)	$ (236)
Beginning balance (shares) at Dec. 31, 2019			652				9
Net income/(loss)		(534)			(534)
Dividends declared		(257)			(257)
Other comprehensive income (loss)		91				91
Common stock issued for employee equity awards	[1]	(5)		29			$ (34)
Common stock issued for employee equity awards (shares)	[1]		1				1
Stock purchased and retired		(344)		(104)	(240)
Stock purchased and retired (shares)			(6)
Ending balance at Mar. 31, 2020		14,309	$ 0	11,054	11,423	(7,898)	$ (270)
Ending balance (shares) at Mar. 31, 2020			647				10
Beginning balance at Dec. 31, 2019		15,358	$ 0	11,129	12,454	(7,989)	$ (236)
Beginning balance (shares) at Dec. 31, 2019			652				9
Net income/(loss)		(11,630)
Ending balance at Sep. 30, 2020		3,357	$ 0	11,241	327	(7,939)	$ (272)
Ending balance (shares) at Sep. 30, 2020			647				10
Beginning balance at Mar. 31, 2020		14,309	$ 0	11,054	11,423	(7,898)	$ (270)
Beginning balance (shares) at Mar. 31, 2020			647				10
Net income/(loss)		(5,717)			(5,717)
Other comprehensive income (loss)		(39)				(39)
Common stock issued for employee equity awards	[1]	37		38			$ (1)
Common stock issued for employee equity awards (shares)	[1]		0				0
Government grant warrant issuance		100		100
Ending balance at Jun. 30, 2020		8,690	$ 0	11,192	5,706	(7,937)	$ (271)
Ending balance (shares) at Jun. 30, 2020			647				10
Net income/(loss)		(5,379)			(5,379)
Other comprehensive income (loss)		(2)				(2)
Common stock issued for employee equity awards	[1]	34		35			$ (1)
Common stock issued for employee equity awards (shares)	[1]		0				0
Government grant warrant issuance		14		14
Ending balance at Sep. 30, 2020		3,357	$ 0	11,241	327	(7,939)	$ (272)
Ending balance (shares) at Sep. 30, 2020			647				10
Beginning balance at Dec. 31, 2020		1,534	$ 0	11,259	(428)	(9,038)	$ (259)
Beginning balance (shares) at Dec. 31, 2020			647				9
Net income/(loss)		(1,177)			(1,177)
Other comprehensive income (loss)		78				78
Common stock issued for employee equity awards	[2]	3		23			$ (20)
Common stock issued for employee equity awards (shares)	[2]		2				1
Government grant warrant issuance		44		44
Ending balance at Mar. 31, 2021		482	$ 0	11,326	(1,605)	(8,960)	$ (279)
Ending balance (shares) at Mar. 31, 2021			649				10
Beginning balance at Dec. 31, 2020		1,534	$ 0	11,259	(428)	(9,038)	$ (259)
Beginning balance (shares) at Dec. 31, 2020			647				9
Ending balance at Jun. 30, 2021		1,281	$ 0	11,396	(953)	(8,882)	$ (280)
Ending balance (shares) at Jun. 30, 2021			650				10
Beginning balance at Dec. 31, 2020		1,534	$ 0	11,259	(428)	(9,038)	$ (259)
Beginning balance (shares) at Dec. 31, 2020			647				9
Net income/(loss)		688
Ending balance at Sep. 30, 2021		2,606	$ 0	11,428	259	(8,800)	$ (281)
Ending balance (shares) at Sep. 30, 2021			650				10
Beginning balance at Mar. 31, 2021		482	$ 0	11,326	(1,605)	(8,960)	$ (279)
Beginning balance (shares) at Mar. 31, 2021			649				10
Net income/(loss)		652			652
Other comprehensive income (loss)		78				78
Common stock issued for employee equity awards	[2]	27		28			$ (1)
Common stock issued for employee equity awards (shares)	[2]		1				0
Government grant warrant issuance		42		42
Ending balance at Jun. 30, 2021		1,281	$ 0	11,396	(953)	(8,882)	$ (280)
Ending balance (shares) at Jun. 30, 2021			650				10
Net income/(loss)		1,212			1,212
Other comprehensive income (loss)		82				82
Common stock issued for employee equity awards	[2]	31		32			$ (1)
Common stock issued for employee equity awards (shares)	[2]		0				0
Ending balance at Sep. 30, 2021		$ 2,606	$ 0	$ 11,428	$ 259	$ (8,800)	$ (281)
Ending balance (shares) at Sep. 30, 2021			650				10

[1] Treasury shares were withheld for payment of taxes, at a weighted average price per share of $56.48, $25.56 and $28.29 in the March 2020 quarter, June 2020 quarter and September 2020 quarter, respectively.

[2] Treasury shares were withheld for payment of taxes, at a weighted average price per share of $38.35, $46.21 and $43.48 in the March 2021 quarter, June 2021 quarter and September 2021 quarter, respectively.