Income Taxes (Details Textuals) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Taxes (Textuals) [Line Items]
Unrecognized tax benefits change as a result of potential resolutions of prior years' tax	$ 3
U.S. statutory federal income tax rate	35.00%	35.00%	35.00%
Out of period tax adjustment			$ 11
Accumulated earnings intended to be permanently reinvested outside the U.S.		$ 4,900
Unrecognized tax benefits	$ 24	308	211	$ 364
Unrecognized tax benefits that effect effective tax rate	19	12	14
Unrecognized tax benefits income tax penalties and interest expense	1	2	$ 1
Unrecognized tax benefits income tax penalties and interest accrued	5	48
Current federal taxes payable/receivable	786	17
Income tax paid/refund net	(308)	45
Tax benefit recognized in subsequent period		289
Out of period tax rate adjustment			4.40%
Tax positions related to prior years	(289)	$ (1)	$ (152)
U.S. Tax Act Discrete Net Charge	858
U.S. Tax Act Deemed Repatriation of Taxes	737
U.S. Tax Act Deferred Tax on distribution of foreign subs earnings	105
U.S. Tax Act Remeasurement Of Deferred Tax Assets and Liabilities	16
Deemed Repatriation Tax Payments Due By Year Total	$ 729
Tax Year 2018 [Member]
Income Taxes (Textuals) [Line Items]
U.S. statutory federal income tax rate	21.00%
Twelve Month [Member]
Income Taxes (Textuals) [Line Items]
Unrecognized tax benefits that effect effective tax rate	$ 2
Resolution Of Uncertain Tax Positions [Member]
Income Taxes (Textuals) [Line Items]
Unrecognized tax benefits income tax penalties and interest accrued	$ 42
Internal Revenue Service (IRS) [Member] | Earliest Year [Member]
Income Tax Contingency [Line Items]
Open tax years by major tax jurisdiction	2008
Internal Revenue Service (IRS) [Member] | Latest Year [Member]
Income Tax Contingency [Line Items]
Open tax years by major tax jurisdiction	2014