Basis of Presentation and Significant Accounting Policies Supplemental Cash Flow information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020
Reduction in Long-term Debt Through Long-term Debt Exchange	$ 0		$ 71
Exchange of investments in Puerto Rico bonds for new securities issued in the restructuring transactions	185
Income Taxes Paid	2	$ 8
Cash and cash equivalents	60	23	17
Restricted Cash	7	16	5
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	116	42	23	$ 35
Long-term Debt [Member]
Interest Paid, Including Capitalized Interest, Operating and Investing Activities	15	25
Variable Interest Entity, Primary Beneficiary [Member]
Restricted Cash	$ 49	$ 2	$ 2