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		(12)		(1,933)
Net earnings	$ 1,015			1,015
Dividends declared				(297)
Stock compensation		1		(13)
Other comprehensive income, net of tax	175				175
End of period at Jun. 30, 2015	$ 6,171	188	0	11,164	(5,181)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared per share	$ 1.50
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		(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