Other Comprehensive Earnings/Losses (Reclassifications) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net periodic benefit income, excluding service cost									$ (77)	$ (37)	$ (34)
Earnings from equity investment in ABI									211	(1,725)	(890)
Pre-tax amounts reclassified from accumulated other comprehensive losses to net earnings (losses)	$ (1,922)	$ 956	$ (1,938)	$ (1,550)	$ 1,814	$ 2,602	$ (1,997)	$ (1,121)	(4,454)	1,298	(6,967)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings from equity investment in ABI									21	(34)	(64)
Pre-tax amounts reclassified from accumulated other comprehensive losses to net earnings (losses)									169	139	177
Reclassification out of Accumulated Other Comprehensive Income [Member] | Net loss [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net periodic benefit income, excluding service cost									173	200	276
Reclassification out of Accumulated Other Comprehensive Income [Member] | Prior service costs/credit [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net periodic benefit income, excluding service cost									(25)	(27)	(35)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Benefit Plans [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net periodic benefit income, excluding service cost									$ 148	$ 173	$ 241