Long-Term Debt and Revolving Credit Arrangements - Interest Expense (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Debt Disclosure [Abstract]
Contractual interest coupon	$ 140	$ 32
Amortization of debt discount and issuance costs	53	72
8% IRR payout	17	14
Total interest expense from long-term debt	$ 210	$ 118