Basis Of Presentation (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		6 Months Ended		12 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2015
Basis of Presentation [Line Items]
Net earnings		$ 2,196	$ 1,749	$ 4,673	$ 3,328
Increase/(Decrease) in revenue due to change in accounting estimate		(72)	263	45	470
Increase/(Decrease) in Earnings from operations due to change in accounting estimate		$ (237)	$ 314	$ (159)	$ 422
Change in Earnings Per Share Due to Change in Accounting Estimate		$ (0.34)	$ 0.37	$ (0.23)	$ 0.50
Retained earnings		$ 52,303		$ 52,303		$ 49,618
Accumulated Other Comprehensive Income (Loss), Net of Tax	[1]	$ (16,139)	$ (13,234)	(16,139)	$ (13,234)	(16,373)	$ (13,623)	$ (16,162)	$ (13,415)
Accounting Standards Update 2014-09 [Member]
Basis of Presentation [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption						1,301	139			$ 901
Net earnings						261	$ 139
Adjustments for New Accounting Pronouncement [Member]
Basis of Presentation [Line Items]
Net earnings			$ (12)		116
Retained earnings						4,298
Accumulated Other Comprehensive Income (Loss), Net of Tax						(2,997)
Accounting Standards Update 2018-02 [Member]
Basis of Presentation [Line Items]
Retained earnings						2,997
Accumulated Other Comprehensive Income (Loss), Net of Tax						(2,997)
Retained Earnings [Member]
Basis of Presentation [Line Items]
Net earnings				$ 4,673	$ 3,328
Retained Earnings [Member] | Accounting Standards Update 2014-09 [Member]
Basis of Presentation [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption						$ 1,301				$ 901

[1] Net of tax.