Condensed Consolidated Statement of Stockholders' Equity - USD ($) $ in Millions	Total	Cumulative effect of adopting Accounting Standards Update No. 2016-01, Financial Instruments (See Note 1)	Common Stock	Capital in excess of par value	Retained earnings	Retained earnings Cumulative effect of adopting Accounting Standards Update No. 2016-01, Financial Instruments (See Note 1)	Accumulated other comprehensive income (loss)	Accumulated other comprehensive income (loss) Cumulative effect of adopting Accounting Standards Update No. 2016-01, Financial Instruments (See Note 1)	Treasury stock
Balance at beginning of period at Dec. 31, 2019	$ 9,832		$ 808	$ 1,581	$ 17,945		$ (61)		$ (10,441)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock	(451)								(451)
Issuance of common and treasury stock pursuant to Employee stock plans	(2)			(8)					6
Share-based compensation	9			9
Cash dividends	(94)				(94)
Comprehensive income (loss)	(219)				(94)		(125)
Balance at end of period at Mar. 31, 2020	9,075		808	1,582	17,757		(186)		(10,886)
Balance at beginning of period at Dec. 31, 2019	9,832		808	1,581	17,945		(61)		(10,441)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	(1,078)
Balance at end of period at Jun. 30, 2020	10,878		888	4,159	16,842		(130)		(10,881)
Balance at beginning of period at Mar. 31, 2020	9,075		808	1,582	17,757		(186)		(10,886)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net of issuance costs	2,224		80	2,144
Issuance of common and treasury stock pursuant to Employee stock plans	13			8					5
Share-based compensation	(2)			(2)
Stock warrants	35			35
Equity feature of convertible notes, net of issuance costs	392			392
Comprehensive income (loss)	(859)				(915)		56
Balance at end of period at Jun. 30, 2020	10,878		888	4,159	16,842		(130)		(10,881)
Balance at beginning of period at Dec. 31, 2020	8,876	$ 0	888	4,191	14,777	$ 19	(105)	$ (19)	(10,875)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common and treasury stock pursuant to Employee stock plans	0			(8)					8
Share-based compensation	14			14
Stock warrants	23			23
Comprehensive income (loss)	180				116		64
Balance at end of period at Mar. 31, 2021	9,093		888	4,220	14,912		(60)		(10,867)
Balance at beginning of period at Dec. 31, 2020	8,876	$ 0	888	4,191	14,777	$ 19	(105)	$ (19)	(10,875)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	723
Balance at end of period at Jun. 30, 2021	9,688		888	4,269	15,260		136		(10,865)
Balance at beginning of period at Mar. 31, 2021	9,093		888	4,220	14,912		(60)		(10,867)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common and treasury stock pursuant to Employee stock plans	13			11					2
Share-based compensation	16			16
Stock warrants	22			22
Comprehensive income (loss)	544				348		196
Balance at end of period at Jun. 30, 2021	$ 9,688		$ 888	$ 4,269	$ 15,260		$ 136		$ (10,865)