Other Comprehensive Earnings/Losses (Reclassifications) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net periodic benefit income, excluding service cost	$ (28)	$ (15)	$ (55)	$ (16)
Earnings from equity investments	9	447	166	533
Pre-tax amounts reclassified from accumulated other comprehensive losses to net earnings	(1,938)	(1,997)	(3,488)	(3,118)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings from equity investments	8	19	15	31
Pre-tax amounts reclassified from accumulated other comprehensive losses to net earnings	20	20	41	47
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	28	39	56	78
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	35	44	69	93
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	$ (7)	$ (5)	$ (13)	$ (15)