Accrued Expenses And Other Payables (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Unrealized losses on derivative contracts	$ 464	$ 651
Reinsurance Payable	111	479
Liability for Claims and Claims Adjustment Expense	268	373
Deferred income	789	1,065
Other accruals and payables	1,201	1,414
Total accrued expenses and other payables	$ 2,833	$ 3,982