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, 2014		$ 199	$ 0	$ 12,392	$ (5,356)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock repurchased		(18)		(2,872)
Net earnings	$ 1,531			1,531
Dividends declared				(447)
Stock compensation		2		9
Other comprehensive income, net of tax	257				257
End of period at Sep. 30, 2015	$ 5,697	183	0	10,613	(5,099)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared per share	$ 2.30
Beginning of year at Dec. 31, 2015	$ 5,522	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		(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