Benefit Plans (Movements in Other Comprehensive Earnings/Losses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net loss	$ 296	$ 187	$ 340
Prior service cost/credit	(32)	(33)	(35)
Net loss, other expense (income)	8		6
Deferred income taxes	(105)	(60)	(120)
Amounts reclassified to net earnings as components of net periodic benefit cost	167	94	191
Net loss, Other movements during the year	(223)	(1,411)	1,568
Prior service cost/credit, Other movements during the year	0		(9)
Deferred income taxes, Other movements during the year	86	550	(609)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Reclassification Adjustments, Net of Tax	(137)	(861)	950
Total movements in other comprehensive earnings/losses	30	(767)	1,141
Pension [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net loss	234	147	271
Prior service cost/credit	7	10	10
Net loss, other expense (income)	8		6
Deferred income taxes	(96)	(61)	(111)
Amounts reclassified to net earnings as components of net periodic benefit cost	153	96	176
Net loss, Other movements during the year	(410)	(1,093)	1,218
Prior service cost/credit, Other movements during the year	(6)		(7)
Deferred income taxes, Other movements during the year	160	425	(470)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Reclassification Adjustments, Net of Tax	(256)	(668)	741
Total movements in other comprehensive earnings/losses	(103)	(572)	917
Postretirement Benefit Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net loss	43	22	51
Prior service cost/credit	(39)	(43)	(45)
Net loss, other expense (income)	0		0
Deferred income taxes	(2)	8	(2)
Amounts reclassified to net earnings as components of net periodic benefit cost	2	(13)	4
Net loss, Other movements during the year	192	(306)	327
Prior service cost/credit, Other movements during the year	6		(2)
Deferred income taxes, Other movements during the year	(75)	120	(129)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Reclassification Adjustments, Net of Tax	123	(186)	196
Total movements in other comprehensive earnings/losses	125	(199)	200
Postemployment Benefit Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net loss	19	18	18
Prior service cost/credit	0	0	0
Net loss, other expense (income)	0		0
Deferred income taxes	(7)	(7)	(7)
Amounts reclassified to net earnings as components of net periodic benefit cost	12	11	11
Net loss, Other movements during the year	(5)	(12)	23
Prior service cost/credit, Other movements during the year	0		0
Deferred income taxes, Other movements during the year	1	5	(10)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Reclassification Adjustments, Net of Tax	(4)	(7)	13
Total movements in other comprehensive earnings/losses	$ 8	$ 4	$ 24