Income Taxes - Income Tax (Benefit) Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current Income Tax Expense (Benefit) [Abstract]
Total current income tax expense	$ 304	$ 358	$ 354
Deferred Income Tax Benefit [Abstract]
Total deferred income tax benefit	(102)	(194)	(396)
Income tax expense (benefit)	202	164	(42)
Ireland [Member]
Current Income Tax Expense (Benefit) [Abstract]
Ireland	2	8	(13)
Deferred Income Tax Benefit [Abstract]
Ireland	2	1	2
United States - Federal [Member]
Current Income Tax Expense (Benefit) [Abstract]
United States - Federal	95	88	87
Deferred Income Tax Benefit [Abstract]
United States - Federal	(72)	(65)	(224)
State and Local Jurisdiction [Member]
Current Income Tax Expense (Benefit) [Abstract]
United States - State and local	(2)	22	41
Deferred Income Tax Benefit [Abstract]
United States - State and local	(2)	(6)	(49)
Foreign - other [Member]
Current Income Tax Expense (Benefit) [Abstract]
Foreign - other	209	240	239
Deferred Income Tax Benefit [Abstract]
Foreign - other	$ (30)	$ (124)	$ (125)