Pension and Other Postretirement Benefit Plans (Other Changes in Plan Assets and Benefit Obligations Recognized in OCI (Pre-Tax) in 2011) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Current year actuarial loss	$ 102	$ 51	$ 139
Total recognized in other comprehensive income (loss) (pre-tax)	48	$ 15	$ 70
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Current year actuarial loss	(16)
Actuarial (loss) recognized during the year	0
Current year prior service cost (credit)	4
Prior service credit (cost) recognized during the year	0
Total recognized in other comprehensive income (loss) (pre-tax)	(12)
Total recognized in net periodic benefit costs and other comprehensive income (loss) (pre-tax)	10
United States Pension Benefits | Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Current year actuarial loss	118
Actuarial (loss) recognized during the year	(53)
Current year prior service cost (credit)	0
Prior service credit (cost) recognized during the year	3
Total recognized in other comprehensive income (loss) (pre-tax)	68
Total recognized in net periodic benefit costs and other comprehensive income (loss) (pre-tax)	68
Foreign Pension Benefits | Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Current year actuarial loss	0
Actuarial (loss) recognized during the year	(9)
Current year prior service cost (credit)	1
Prior service credit (cost) recognized during the year	0
Total recognized in other comprehensive income (loss) (pre-tax)	(8)
Total recognized in net periodic benefit costs and other comprehensive income (loss) (pre-tax)	$ (4)