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, 2015		$ 181	$ 0	$ 10,661	$ (5,320)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock repurchased		(6)		(1,154)
Net earnings	$ 1,675			1,675
Dividends declared				(472)
Stock compensation		2	0	(82)
Other comprehensive income, net of tax	282				282
End of period at Sep. 30, 2016	$ 5,767	177	0	10,628	(5,038)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared per share	$ 2.60
Beginning of year at Dec. 31, 2016	$ 5,259	175	0	10,630	(5,546)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock repurchased		(2)		(371)
Net earnings	1,837			1,837
Dividends declared				(511)
Stock compensation		1	16	(39)
Other comprehensive income, net of tax	303				303
End of period at Sep. 30, 2017	$ 6,493	$ 174	$ 16	$ 11,546	$ (5,243)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared per share	$ 2.90