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	(371)
Net earnings	$ 1,848			1,848
Dividends declared				(511)
Stock compensation		1	16	(39)
Other comprehensive income, net of tax	303				303
End of period at Sep. 30, 2017	$ 6,608	174	16	11,661	(5,243)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared per share	$ 2.90
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		(1)	(34)	(179)
Net earnings	2,572			2,572
Dividends declared				(616)
Stock compensation		1	(10)	(9)
Other comprehensive income, net of tax	247				247
End of period at Sep. 30, 2018	$ 9,103	$ 174	$ 0	$ 14,464	$ (5,535)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared per share	$ 3.50