Condensed Consolidated Statement of Stockholders' Equity Statement - USD ($) $ in Millions	Total	Treasury stock	Accumulated other comprehensive income (loss)	Retained earnings	Capital in excess of par value	Common Stock
Cumulative effect of new accounting standards	$ (55)	$ 0	$ 0	$ 55	$ 0	$ 0
Balance at beginning of period at Dec. 31, 2018	9,853	(8,452)	20	15,967	1,510	808
Balance at beginning of period (Accounting Standards Update 2016-02) at Dec. 31, 2018	9,908	(8,452)	20	16,022	1,510	808
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock	(500)	(500)	0	0	0	0
Issuance of common and treasury stock pursuant to Employee stock plans	4	6	0	0	10	0
Share-based compensation	$ (13)	0	0	0	(13)	0
Cash dividends, per share (in dollars per share)	$ 0.160
Cash dividends	$ (89)	0	0	(89)	0	0
Comprehensive income (loss)	463	0	76	387	0	0
Balance at end of period at Mar. 31, 2019	9,791	(8,946)	96	16,320	1,513	808
Balance at beginning of period at Dec. 31, 2018	9,853	(8,452)	20	15,967	1,510	808
Balance at beginning of period (Accounting Standards Update 2016-02) at Dec. 31, 2018	9,908	(8,452)	20	16,022	1,510	808
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	1,704
Balance at end of period at Sep. 30, 2019	9,931	(9,893)	(63)	17,525	1,554	808
Balance at beginning of period at Mar. 31, 2019	9,791	(8,946)	96	16,320	1,513	808
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock	(450)	(450)	0	0	0	0
Issuance of common and treasury stock pursuant to Employee stock plans	10	2	0		8	0
Share-based compensation	$ (13)	0	0	0	(13)	0
Cash dividends, per share (in dollars per share)	$ 0.180
Cash dividends	$ (99)	0	0	(99)	0	0
Comprehensive income (loss)	675	0	(66)	741	0	0
Balance at end of period at Jun. 30, 2019	9,940	(9,394)	30	16,962	1,534	808
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock	(500)	(500)	0	0	0	0
Issuance of common and treasury stock pursuant to Employee stock plans	9	1	0	0	8	0
Share-based compensation	$ (12)	0	0	0	(12)	0
Cash dividends, per share (in dollars per share)	$ 0.180
Cash dividends	$ (96)	0	0	(96)	0	0
Comprehensive income (loss)	566	0	(93)	659	0	0
Balance at end of period at Sep. 30, 2019	9,931	(9,893)	(63)	17,525	1,554	808
Balance at beginning of period at Dec. 31, 2019	9,832	(10,441)	(61)	17,945	1,581	808
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock	(451)	(451)	0	0	0	0
Issuance of common and treasury stock pursuant to Employee stock plans	2	6	0	0	8	0
Share-based compensation	$ (9)	0	0	0	(9)	0
Cash dividends, per share (in dollars per share)	$ 0.180
Cash dividends	$ (94)	0	0	(94)	0	0
Comprehensive income (loss)	(219)	0	(125)	(94)	0	0
Balance at end of period at Mar. 31, 2020	9,075	(10,886)	(186)	17,757	1,582	808
Balance at beginning of period at Dec. 31, 2019	9,832	(10,441)	(61)	17,945	1,581	808
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	(2,207)
Balance at end of period at Sep. 30, 2020	9,769	(10,877)	(102)	15,685	4,175	888
Balance at beginning of period at Mar. 31, 2020	9,075	(10,886)	(186)	17,757	1,582	808
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net of issuance costs	2,224	0	0	0	2,144	80
Issuance of common and treasury stock pursuant to Employee stock plans	13	5	0	0	8	0
Share-based compensation	(2)	0	0	0	(2)	0
Stock warrants	35	0	0	0	35	0
Equity feature of convertible notes, net of issuance costs	392	0	0	0	392	0
Comprehensive income (loss)	(859)	0	56	(915)	0	0
Balance at end of period at Jun. 30, 2020	10,878	(10,881)	(130)	16,842	4,159	888
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common and treasury stock pursuant to Employee stock plans	13	4	0	0	9	0
Share-based compensation	(2)	0	0	0	(2)	0
Stock warrants	5	0	0	0	5	0
Comprehensive income (loss)	(1,129)	0	28	(1,157)	0	0
Balance at end of period at Sep. 30, 2020	$ 9,769	$ (10,877)	$ (102)	$ 15,685	$ 4,175	$ 888