Goodwill and Other Intangible Assets - Changes in Goodwill and Other Intangible Assets (Details) $ in Millions	9 Months Ended
	Sep. 30, 2017 USD ($)
Goodwill and Other Intangible Assets [Roll Forward]
Amortizing Intangible Assets, Beginning Balance	$ 285
Amortizing Intangible Assets, Amortization expense	(49)
Finite-Lived Intangible Assets, Other Charges	0
Amortizing Intangible Assets, Ending Balance	236
Goodwill, Beginning Balance	1,608
Goodwill, Other Increase (Decrease)	0
Goodwill, Ending Balance	1,608
Other Non-Amortizing Intangible Assets, Beginning Balance	148
Indefinite-lived Intangible Assets, Other Charges	(22)
Other Non-Amortizing Intangible Assets, Ending Balance	$ 126