Other Comprehensive Earnings/Losses (Reclassifications) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net periodic benefit income, excluding service cost	$ (3)	$ (24)	$ (58)	$ (40)
(Earnings) losses from equity investments	472	(333)	306	(866)
Pre-tax amounts reclassified from accumulated other comprehensive losses to net earnings (losses)	956	2,602	(2,532)	(516)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
(Earnings) losses from equity investments	44	(4)	29	(35)
Pre-tax amounts reclassified from accumulated other comprehensive losses to net earnings (losses)	99	31	140	78
Benefit Plans [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net periodic benefit income, excluding service cost	55	35	111	113
Net loss [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net periodic benefit income, excluding service cost	60	42	129	135
Prior service cost/credit [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net periodic benefit income, excluding service cost	$ (5)	$ (7)	$ (18)	$ (22)