Fair Value Measurements - Assets and Liabilities Measured on a Recurring Basis (Details) - Recurring Basis [Member] - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Assets:
Cash equivalents	$ 11	$ 16
Restricted cash equivalents	5	0
Interest rate contracts	54	9
Total assets	70	25
Liabilities:
Interest rate contracts	1,268	427
Total liabilities	1,268	427
Level 1 [Member]
Assets:
Cash equivalents	11	16
Restricted cash equivalents	5	0
Interest rate contracts	0	0
Total assets	16	16
Liabilities:
Interest rate contracts	0	0
Total liabilities	0	0
Level 2 [Member]
Assets:
Cash equivalents	0	0
Restricted cash equivalents	0	0
Interest rate contracts	54	9
Total assets	54	9
Liabilities:
Interest rate contracts	1,268	427
Total liabilities	$ 1,268	$ 427