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 year at Dec. 31, 2016		$ 175	$ 0	$ 10,734	$ (5,546)
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	(351)
Net earnings	$ 1,205			1,205
Dividends declared				(336)
Stock compensation		1	0	(48)
Other comprehensive income, net of tax	204				204
End of period at Jun. 30, 2017	$ 6,036	174	0	11,204	(5,342)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared per share	$ 1.90
Beginning of year at Dec. 31, 2017	$ 7,132	174	44	11,632	(4,718)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Impact from adoption of ASU 2018-02 and ASU 2016-01				1,064	(1,064)
Common stock repurchased		0	(34)	(15)
Net earnings	1,428			1,428
Dividends declared				(405)
Stock compensation		0	(10)	(35)
Other comprehensive income, net of tax	166				166
End of period at Jun. 30, 2018	$ 8,227	$ 174	$ 0	$ 13,669	$ (5,616)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared per share	$ 2.30