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		(5)		(854)
Net earnings	$ 484			484
Dividends declared				(142)
Stock compensation		1		(37)
Other comprehensive income, net of tax	66				66
End of period at Mar. 31, 2015	$ 6,748	195	0	11,843	(5,290)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared per share	$ 0.7
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		(2)		(284)
Net earnings	556			556
Dividends declared				(147)
Stock compensation		2		(122)
Other comprehensive income, net of tax	96				96
End of period at Mar. 31, 2016	$ 5,621	$ 181	$ 0	$ 10,664	$ (5,224)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared per share	$ 0.8