Goodwill (details) - Other Intangible Assets - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Goodwill and Other Intangible Assets disclosure
Intangible assets subject to amortization, gross carrying amount	$ 210		$ 210		$ 210
Intangible assets subject to amortization, accumulated amortization	153		153		148
Intangible assets subject to amortization, net	57		57		62
Intangible assets not subject to amortization	217		217		217
Total other intangible assets, gross carrying amount	427		427		427
Total other intangible assets, net	274		274		$ 279
Amortization expense of intangible assets	2	$ 9	5	$ 20
Estimated intangible asset amortization expense, remainder of 2016	5		5
Estimated intangible asset amortization expense, 2017	9		9
Estimated intangible asset amortization expense, 2018	8		8
Estimated intangible asset amortization expense, 2019	7		7
Estimated intangible asset amortization expense, 2020	$ 5		$ 5