Benefit Plans (Movements in Other Comprehensive Earnings (Losses)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Amortization:
Net losses	$ 278	$ 247	$ 248
Prior service cost	31	(1)	5
Net transition obligation		1
Other income/expense:
Net losses	3	14	6
Deferred income taxes	(69)	(43)	(31)
Amortization of net losses, prior service costs and net transition costs	243	218	228
Other movements during the year:
Prior service cost			0
Deferred income taxes	247	65	(17)
Net gains (losses) and prior service costs	(454)	(1,046)	523
Accumulated Other Comprehensive Losses [Member]
Other movements during the year:
Net losses	(698)	(1,121)	525
Prior service cost	(2)	8	13
Deferred income taxes	247	65	(17)
Net gains (losses) and prior service costs	(426)	(1,048)	521
Total movements in other comprehensive earnings (losses)	(183)	(830)	749
Pension [Member]
Amortization:
Net losses	198	180	175
Prior service cost	32	0	5
Net transition obligation		1
Other income/expense:
Net losses	3	14	6
Deferred income taxes	(51)	(28)	(10)
Amortization of net losses, prior service costs and net transition costs	182	167	176
Other movements during the year:
Net losses	(521)
Prior service cost	(2)
Deferred income taxes	206
Net gains (losses) and prior service costs	(291)
Total movements in other comprehensive earnings (losses)	(109)
Pension [Member] | Accumulated Other Comprehensive Losses [Member]
Other movements during the year:
Net losses		(1,008)	509
Prior service cost		8	13
Deferred income taxes		80	(13)
Net gains (losses) and prior service costs		(920)	509
Total movements in other comprehensive earnings (losses)		(753)	685
Postretirement [Member]
Amortization:
Net losses	3	5	5
Prior service cost	(1)	(1)	0
Net transition obligation		0
Other income/expense:
Net losses	0	0	0
Deferred income taxes	(1)	(1)	(1)
Amortization of net losses, prior service costs and net transition costs	1	3	4
Other movements during the year:
Net losses	(27)	34	(12)
Prior service cost	0	0	0
Deferred income taxes	6	(7)	5
Net gains (losses) and prior service costs	(20)	27	(7)
Total movements in other comprehensive earnings (losses)	(19)	30	(3)
Postemployment Benefit Plans [Member]
Amortization:
Net losses	77	62	68
Prior service cost	0	0	0
Net transition obligation		0
Other income/expense:
Net losses	0	0	0
Deferred income taxes	(17)	(14)	(20)
Amortization of net losses, prior service costs and net transition costs	60	48	48
Other movements during the year:
Net losses	(150)	(147)	28
Prior service cost	0	0
Deferred income taxes	35	(8)	(9)
Net gains (losses) and prior service costs	(115)	(155)	19
Total movements in other comprehensive earnings (losses)	(55)	(107)	67
Deconsolidation of RBH [Member]
Other income/expense:
Deferred income taxes	(15)	0	0
Amortization of net losses, prior service costs and net transition costs	27	$ 0	$ 0
Deconsolidation of RBH [Member] | Accumulated Other Comprehensive Losses [Member]
Other movements during the year:
Deconsolidation of RBH (net of deferred income taxes)	27
Deconsolidation of RBH [Member] | Pension [Member]
Other movements during the year:
Deconsolidation of RBH (net of deferred income taxes)	26
Deconsolidation of RBH [Member] | Postretirement [Member]
Other movements during the year:
Deconsolidation of RBH (net of deferred income taxes)	$ 1