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, 2016		$ 175	$ 0	$ 10,734	$ (5,546)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Impact from adoption of ASU 2018-02 and ASU 2016-01				0	0
Common stock repurchased		(1)		(215)
Net earnings	$ 650			650
Dividends declared				(159)
Stock compensation		1	0	(72)
Other comprehensive income, net of tax	105				105
End of period at Mar. 31, 2017	$ 5,672	175	0	10,938	(5,441)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared per share	$ 0.90
Beginning of year at Dec. 31, 2017	$ 7,132	174	44	11,632	(4,718)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Impact from adoption of ASU 2018-02 and ASU 2016-01				1,064	(1,064)
Common stock repurchased		0		0
Net earnings	739			739
Dividends declared				(195)
Stock compensation		0	(44)	(35)
Other comprehensive income, net of tax	83				83
End of period at Mar. 31, 2018	$ 7,680	$ 174	$ 0	$ 13,205	$ (5,699)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared per share	$ 1.10