Long-Term Debt (Schedule of Extinguishment of Debt) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2019 USD ($)
Details underlying the recognition of gain or loss on extinguishment of debt [Abstract]
Principal balance outstanding prior to payoff	$ 109	[1]
Unamortized debt issuance costs and discounts prior to payoff	(1)
Amount paid to retire debt	(150)
Gain (loss) on extinguishment of debt, pre-tax	(42)
4.85% Notes, Due 2021 [Member]
Details underlying the recognition of gain or loss on extinguishment of debt [Abstract]
Debt Instrument Repurchase Amount	$ 4
Interest rate	4.85%
6.15% Notes, Due 2036 [Member]
Details underlying the recognition of gain or loss on extinguishment of debt [Abstract]
Debt Instrument Repurchase Amount	$ 105
Interest rate	6.15%

[1] During the third quarter of 2019, we repurchased $105 million of our 6.15% senior notes due 2036 and $4 million of our 4.85% senior notes due 2021.