Income Taxes (Narrative) (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Non Variable Interest Entities [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%
NOL carryforward	$ 2,600
Alternative minimum tax credit carryforward - Other assets	26
Foreign tax credit	62
Unrecognized Tax Benefits	0		$ 0
Valuation allowance on net deferred tax asset	$ 839		$ 834