Condensed Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Millions	Total	Common stock	Paid-in capital	Retained earnings	Accumulated other comprehensive (loss) income
Beginning of period at Dec. 31, 2017		$ 174	$ 44	$ 6,913	$ 1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Impact from adoption of ASU 2018-02 and ASU 2016-01				(21)	21
Common stock repurchased		0	(34)	(15)
Net earnings	$ 1,629			1,629
Dividends declared				(405)
Stock compensation			(10)	(35)
Other comprehensive loss, net of tax	(36)				(36)
End of period at Jun. 30, 2018	$ 8,226	174	0	8,066	(14)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared per share	$ 2.30
Beginning of period at Mar. 31, 2018		174	0	7,502	4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Impact from adoption of ASU 2018-02 and ASU 2016-01				0	0
Common stock repurchased		0	(34)	(15)
Net earnings	$ 789			789
Dividends declared				(210)
Stock compensation			34	0
Other comprehensive loss, net of tax	(18)				(18)
End of period at Jun. 30, 2018	$ 8,226	174	0	8,066	(14)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared per share	$ 1.20
Beginning of period at Dec. 31, 2018	$ 8,187	171	0	8,068	(52)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Impact from adoption of ASU 2018-02 and ASU 2016-01				0	0
Common stock repurchased		(2)	0	(234)
Net earnings	1,724			1,724
Dividends declared				(432)
Stock compensation			0	(6)
Other comprehensive loss, net of tax	(23)				(23)
End of period at Jun. 30, 2019	$ 9,214	169	0	9,120	(75)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared per share	$ 2.52
Beginning of period at Mar. 31, 2019		170	0	8,628	(59)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Impact from adoption of ASU 2018-02 and ASU 2016-01				0	0
Common stock repurchased		(1)	0	(172)
Net earnings	$ 861			861
Dividends declared				(226)
Stock compensation			0	29
Other comprehensive loss, net of tax	(16)				(16)
End of period at Jun. 30, 2019	$ 9,214	$ 169	$ 0	$ 9,120	$ (75)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared per share	$ 1.32