Equity (Capital Transactions) (Detail - Narrative) - USD ($) $ in Millions					3 Months Ended		9 Months Ended
	Sep. 08, 2017	Aug. 10, 2017	Jun. 30, 2017	Apr. 28, 2017	Sep. 30, 2017	Mar. 31, 2017	Sep. 30, 2017
Adjustments To Additional Paid In Capital, Capital Contribution						$ (202)
Amount of other increase (decrease) in additional paid in capital (APIC) due to a return of capital				$ 2,700			$ 2,737
Cash Capital Contribution
Adjustments To Additional Paid In Capital, Capital Contribution	$ 100	$ 400	$ 600
Non-cash Contribution
Adjustments To Additional Paid In Capital, Capital Contribution			$ 750		$ 1,100