Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2016

Commitments And Contingencies [Abstract]

Future Minimum Rental Commitments for All Long-Term Noncancelable Operating Leases

($ in millions)	Operating Leases
Year ending December 31:
2017	$	91
2018		18
2019		18
2020		23
2021		21
Thereafter		76
Total minimum lease payments	$	247

Future Payments for Obligations under Noncancelable Long Distance Contracts and Service Agreements

($ in millions)	Amount
Year ending December 31:
2017	$	42
2018		41
2019		7
2020		6
2021		2
Thereafter		10
Total	$	108

Outstanding Performance Letters of Credit

($ in millions)	Amount
CNA Financial Corporation (CNA)	$	49
AIG Insurance		75
All other		1
Total	$	125