Condensed Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Millions	Total	Common stock	Paid-in capital	Retained earnings	Accumulated other comprehensive loss
Beginning of period at Dec. 31, 2018		$ 171	$ 0	$ 8,068	$ (52)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock repurchased		(2)		(449)
Net earnings	$ 2,657			2,657
Dividends declared				(658)
Stock compensation			0	31
Other			0	0
Other comprehensive loss, net of tax	(35)				(35)
End of period at Sep. 30, 2019	$ 9,731	169	0	9,649	(87)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared per share	$ 3.84
Beginning of period at Jun. 30, 2019		169	0	9,120	(75)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock repurchased		0		(215)
Net earnings	$ 933			933
Dividends declared				(226)
Stock compensation			0	37
Other			0	0
Other comprehensive loss, net of tax	(12)				(12)
End of period at Sep. 30, 2019	$ 9,731	169	0	9,649	(87)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared per share	$ 1.32
Beginning of period at Dec. 31, 2019	$ 8,819	168	0	8,748	(97)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock repurchased		(1)		(479)
Net earnings	2,859			2,859
Dividends declared				(709)
Stock compensation			33	(36)
Other			(6)	11
Other comprehensive loss, net of tax	(24)				(24)
End of period at Sep. 30, 2020	$ 10,467	167	27	10,394	(121)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared per share	$ 4.22
Beginning of period at Jun. 30, 2020		167	10	9,652	(117)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock repurchased		0		0
Net earnings	$ 986			986
Dividends declared				(244)
Stock compensation			23	0
Other			(6)	0
Other comprehensive loss, net of tax	(4)				(4)
End of period at Sep. 30, 2020	$ 10,467	$ 167	$ 27	$ 10,394	$ (121)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared per share	$ 1.45