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		(3)		(686)
Net earnings	$ 1,073			1,073
Dividends declared				(310)
Stock compensation		1		(104)
Other comprehensive income, net of tax	188				188
End of period at Jun. 30, 2016	$ 5,681	179	0	10,634	(5,132)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared per share	$ 1.70
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)		(351)
Net earnings	1,192			1,192
Dividends declared				(336)
Stock compensation		1		(48)
Other comprehensive income, net of tax	204				204
End of period at Jun. 30, 2017	$ 5,919	$ 174	$ 0	$ 11,087	$ (5,342)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared per share	$ 1.90