Consolidated Statement of Stockholder's Equity - USD ($) $ in Millions	Total	Common Stock	Capital in excess of par value	Retained earnings	Accumulated other comprehensive income (loss)	Treasury stock
Balance at beginning of period at Dec. 31, 2016	$ 7,784	$ 808	$ 1,410	$ 10,761	$ (323)	$ (4,872)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock	(1,600)	0	0	0	0	(1,600)
Issuance of common and treasury stock pursuant to Employee stock plans	14	0	4	0	0	10
Share-based compensation	37	0	37	0	0	0
Cash dividends	(286)	0	0	(286)	0	0
Comprehensive income	3,692	0	0	3,357	335	0
Balance at end of period at Dec. 31, 2017	9,641	808	1,451	13,832	12	(6,462)
Balance at end of period (ASU 2017-12) at Dec. 31, 2017	9,641	808	1,451	13,850	(6)	(6,462)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of new accounting standards	0	0	0	18	(18)	0
Repurchase of common stock	(2,000)	0	0	0	0	(2,000)
Issuance of common and treasury stock pursuant to Employee stock plans	23	0	13	0	0	10
Share-based compensation	46	0	46	0	0	0
Cash dividends	(348)	0	0	(348)	0	0
Comprehensive income	2,491	0	0	2,465	26	0
Balance at end of period at Dec. 31, 2018	9,853	808	1,510	15,967	20	(8,452)
Balance at end of period (ASU 2016-02) at Dec. 31, 2018	9,908	808	1,510	16,022	20	(8,452)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of new accounting standards	55	0	0	55	0	0
Repurchase of common stock	(2,000)	0	0	0	0	(2,000)
Issuance of common and treasury stock pursuant to Employee stock plans	27	0	16	0	0	11
Share-based compensation	55	0	55	0	0	0
Cash dividends	(377)	0	0	(377)	0	0
Comprehensive income	2,219	0	0	2,300	(81)	0
Balance at end of period at Dec. 31, 2019	$ 9,832	$ 808	$ 1,581	$ 17,945	$ (61)	$ (10,441)