Income Taxes Level 4 (Details) - Unrecognized Tax Benefits - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of year	$ 73	$ 62
Additions based on tax positions related to the current year	2	4
Additions for tax positions of prior years	1	42
Reductions for tax positions of prior years	(1)	(35)
Settlements	0	0
Foreign currency translation	5	0
Balance at end of year	80	73	$ 62
Unrecognized Tax Benefits, Period Increase (Decrease)	13
Income Tax Examination, Penalties Expense	5	6	$ 4
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	49	$ 43
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	80
Maximum [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Amount of Unrecognized Tax Benefits Expected to Be Recognized within the Next 12 Months	$ 2