Debt And Shareholders' Equity (Narrative) (Details) - USD ($)
$ / shares in Units, $ in Millions

3 Months Ended

Mar. 31, 2019

Mar. 31, 2019

Mar. 31, 2018

Apr. 30, 2019

Dec. 31, 2018

Dec. 31, 2017

Debt And Shareholders' Equity [Line Items]

Schedule of Long-term Debt Instruments [Table Text Block]

Long-term debt is summarized as follows:

(In millions)	March 31, 2019		December 31, 2018
Subordinated notes	$	87	$	87
Senior notes	1,141		637
Total	$	1,228	$	724

Subordinated Debt

$ 87

$ 87

$ 87

Other Comprehensive Income (Loss), before Reclassifications, Net of Tax

127

$ (128)

Stockholders' Equity [Abstract]

Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax

(1)

$ 0

Senior Notes

$ 1,141

$ 1,141

637

Debt Instrument, Interest Rate Terms

0.0335

Entity Common Stock, Shares Outstanding

182,512,940

182,512,940

182,565,329

Common Stock, Par or Stated Value Per Share

$ 0.0010

$ 0.0010

Common Stock

$ 0

$ 0

0

Long-term Debt, Gross

1,228

$ 1,228

724

Stock Repurchased During Period, Shares

5,500,000

2,200,000

Stock Repurchased and Retired During Period, Value

$ 275

$ 115

Treasury Stock Acquired, Average Cost Per Share

$ 50.03

$ 53.46

Stock Repurchase Program, Remaining Authorized Repurchase Amount

$ 275

$ 275

Common Stock, Terms of Conversion

1060000

Accumulated Other Comprehensive Income (Loss), Net of Tax

$ (122)

$ (122)

$ (267)

$ (250)

$ (139)

Warrant [Member]

Stockholders' Equity [Abstract]

Class of Warrant or Right, Outstanding

29,300,000

29,300,000

Warrant Exercise Price

$ 34.61

$ 34.61

Senior Notes [Member]

Stockholders' Equity [Abstract]

Senior Notes

$ 500

$ 500